GHOST WARS

AD 7004

I

The needleship Spear of Orion dropped out of hyperspace. Its tetrahedral Free Earth sigils shone brightly, its weapons ports were open, and its crew were ready to do their duty.

Pilot Officer Hex glanced around the sky, assessing the situation.

She was deep in the Sagittarius Spiral Arm, a place where stars crowded, hot and young. One star was close enough to show a disc, the sun of this system. And there was the green planet she had been sent here to defend. Labelled 147B by the mission planners, this was a terraformed world, a human settlement thrust deep into Silver Ghost territory. But the planet’s face was scarred by fire, immense ships clustered to evacuate the population - and needleships like her own popped into existence everywhere, Aleph Force swimming out of hyperspace like a shoal of fish. This was a battlefield.

All this in a heartbeat. Then the Silver Ghosts attacked.

`Palette at theta ten degrees, phi fifty!’ That was gunner Borno’s voice, coming from the port blister, one of three dotted around the slim waist of the Spear.

Hex, in her own cramped pilot’s blister at the very tip of the needleship, glanced to her left and immediately found the enemy. Needleship crews were warriors in three-dimensional battlefields; translating positional data from one set of spherical coordinates to another was drummed into you before you were five years old.

Borno had found a Ghost intrasystem cruiser, the new kind - a `palette,’ as the analysts were calling them. It was a flat sheet with its Ghost crew sitting in pits in the top surface like blobs of mercury. The ship looked a little like a painter’s palette, hence the nickname. But palettes were fast, manoeuvrable and deadly, much more effective in battle than the classic tangled-rope Ghost ships of the past. And just seconds after she came down from hyperspace this palette was screaming down on Hex, energy weapons firing.

Hex felt her senses come alive, her heartbeat slow to a resolute thump. One of her instructors once said she had been born to end Ghost lives on battlefields. At moments like this, that was how it felt. Hex was twenty years old.

She hauled on her joystick. The needleship swung like a compass needle and hurled itself directly at the Ghost palette. As weapons on both ships fired, the space between them filled with light.

`About time, pilot,’ Borno said. `My fingers were getting itchy.’

`All right, all right,’ Hex snapped back. Gunner Borno, of all the needleship crew she had ever met, had the deepest, most visceral hatred of the Ghosts and all their works. `Just take that thing down before we collide.’

But no lethal blow was struck, and as the distance between the ships closed, uneasiness knotted in Hex’s stomach.

She thumbed a control to give her a magnified view of the palette’s upper surface. She heard her crew murmur in surprise. These Ghosts weren’t the usual silver spheres. They had sharp edges; they were cubes, pyramids, dodecahedrons - even a tetrahedron, as if mocking the ancient symbol of Earth. And they showed no inclination to run away. These were a new breed of Ghost, she realised.

The Spear shuddered. For an instant the Virtual displays clustered around her fritzed, before her systems rebooted and recovered.

`Jul, what was that? Did we take a hit?’

Jul was the ship’s engineer, young, bright, capable - and a good pilot before her lower body was cut away by a lucky strike from a dying Ghost. `Pilot, we ran through g-waves.’

`Gravity waves? From a starbreaker?’

`No,’ called navigator Hella, the last of the Spear’s four crew. `Too long-wavelength for that. And too powerful. Pilot, this space is full of g-waves. That’s how the Ghosts are hitting the planet.’

`Where are they coming from?’

`The scouts can’t find a source.’

`New weapons, new ships, new tactics,’ Borno said darkly.

`And new Ghosts,’ said Hella.

`You know what’s behind this,’ Jul said uneasily.

Hex said warningly, `Engineer-‘

`The Black Ghost. It has to be.’

Unlike any of its kind before, the barracks-room scuttlebutt went, the Black Ghost was an enemy commander that fought like a human - better than a human. The Commissaries claimed this was all just rumour generated by stressed-out crews, but Hex herself had heard that the stories had originated with Ghosts themselves, captives under interrogation. And whether the Black Ghost existed or not, you couldn’t deny that something was making the Ghosts fight better than they ever had.

And meanwhile that palette still hadn’t broken off.

`Thirty seconds to close,’ Hella said. `We won’t survive an impact, pilot.’

`Neither will they,’ Borno said grimly.

`Fifteen seconds.’

`Hold the line!’ Hex ordered.

`Those dimples,’ said engineer Jul hastily. `Where the Ghosts are sitting. There has to be some interface to the palette’s systems. They must be weak spots. Gunner, if you could plant a shell there …’

Hex imagined Borno’s grin.

`Seven seconds! Six!’

A single shell sailed out through the curtain of fire. It was a knot of unified-field energy, like a bit of the universe from a second after the Big Bang itself.

The shell hit a dimple so squarely it probably didn’t even touch the sides. The resident Ghost, a squat cube, was vaporised instantly. Then light erupted from every dimple and weapons port on the palette. The Ghost crew scrambled away, but Hex saw silver skin wrinkle and pop, before the palette vanished in a flash of primordial light.

The needleship slammed through a dissipating cloud of debris, and the blisters turned black to save the crew’s eyes.

The Spear sat in space, its hull charred, still cooling as it dumped the energy it had soaked up. Sparks drifted through the sky: more needleships, a detachment of Aleph Force forming up.

For the first time since they’d dropped out of hyperspace Hex was able to catch her breath, and to take a decent look at the world she had been sent to defend.

Even from here she could see it was suffering. Immense storm systems swathed its poles and catastrophic volcanism turned its nightside bright. Sparks climbed steadily up from the planet’s surface, refugee transports to meet the Navy ships - Spline, living starships, kilometre-wide spheres of flesh and metal.

Hella murmured, `That’s what a g-wave weapon will do to you, if it’s sufficiently powerful.’

Borno asked, `How? By ripping up the surface?’

`Probably by disrupting the planet’s orbital dynamics. You could knock over a world’s spin axis, maybe jolt it into a higher eccentricity orbit. If the core rotation collapsed its magnetic field would implode. You’d have turmoil in the magma currents, earthquakes and volcanism …’

The destruction of a world as an act of war. The people being driven from their homes today were not soldiers. They had come here as colonists, to build a new world. But the very creation of this settlement had been an act of war, Hex knew, for this settlement had been planted deep inside what had been Ghost space until five centuries ago.

The Ghost Wars had already lasted centuries. War with an alien species was not like a human conflict. It was ecological, the Commissaries taught, like two varieties of weed competing for the same bit of soil. It could be terminated by nothing short of total victory - and the price of defeat would be extinction, for one side or another.

And now the Ghosts had a weapon capable of wreaking such damage on a planetary scale, and, worse, were prepared to use it. These were not the Ghosts Hex had spent a lifetime learning to fight. But in that case, she thought harshly, I’ll just have to learn to fight them all over again.

Borno said, `I don’t like just sitting out here.’

`Take it easy,’ Hex said. She downloaded visual feed from the command loops. Ghost ships were being drawn away from the battle around the planet itself, and were heading out to this concentration.

Aleph Force was Strike Arm’s elite, one of the most formidable rapid-response fighting units in the Navy. From their base on the Orion Line they were hurled through hyperspace into the most desperate situations - like this one. Aleph Force always made a difference: that was what their commanders told them to remember. Even the Ghosts had learned that. And that was why Ghosts were peeling off from their main objective to engage them.

`Gunner, we’re giving that evacuation operation a chance just by sitting here. And as soon as we’ve lured in enough Ghosts we’ll take them on. I have a feeling you’ll be slitting hides before the day is done.’

`That might be sooner than you think,’ called engineer Jul, uneasily. `Take a look at this.’ She sent another visual feed around the loop.

Sparks slid around the sky, like droplets of water condensing out of humid air.

Hex had never seen anything like it. `What are they?’

`Ghosts,’ Borno said. `Swarming like flies.’

`They’re all around us,’ Hella breathed. `There must be thousands.’

`Make that millions,’ Jul said. `They’re surrounding the other ships as well.’

Hex called up a magnified visual. As she had glimpsed on the palette, the Ghosts were cubes, pyramids, spinning tetrahedrons, even a few spiny forms like mines.

Jul said, `I thought all Ghosts were spheres.’

Ghosts were hardened to space, and their primary driver was the conservation of their body heat. For a given mass a silvered sphere, the shape with the minimum surface area, was the optimal way to achieve that.

`But they weren’t always like that,’ said Borno. He had studied Ghosts all his life, the better to destroy them. `Ghosts evolved. Maybe these are primitive forms, before they settled for the optimum.’

`Primitive?’ Hex asked. `Then what are they doing here?’

`Don’t ask me.’ His voice was tight. His loathing of Ghosts was no affectation; it was so deep it was almost phobic.

`They’re closing,’ Jul called.

The Spear’s weapons began to spit fire into the converging cloud. Hex saw that one Ghost, two, was caught, flaring and dying in an instant. But it was like firing a laser into a rainstorm.

Hex snapped, `Gunner, you’re just wasting energy.’

`The systems can’t lock,’ Borno said. `Too many targets, too small, too fast-moving.’

`Another new tactic,’ Jul murmured. `And a smart one.’

Navigator Hella called, `Hex, you’d better take a look at this.’

In a new visual, Hex was shown a dense mass of Ghost hide. It was a sheet, a ragged segment of a sphere that grew even as she watched, with more Ghosts clustering around its spreading edges.

`It’s the Ghosts,’ Hella said. `Some of those shapes, for instance the cubes, are space-filling. They’re forming themselves into a shell around us. A solid shell.’

Jul said, wondering, `They are acting in a coordinated way, millions of them, right across the battlefield.’

`Like humans,’ Hella said. `They are fighting like humans, unified under a single command.’

The name hung unspoken between them: this was the work of the Black Ghost.

`We’re losing the comms nets,’ Jul said, tense. `They’re isolating us.’

Hex glanced around the sky. The other needleships of Aleph Force were being enclosed by their own shells of Ghost hide; they hung in space like bizarre silvered fruit. She thought frantically. `If we try to ram that wall-‘

`They’ll just fall back and track us,’ Hella said.

`What if we go to hyperdrive?’

Engineer Jul snapped, `Are you crazy? With all this turbulence in the gravity field, surrounded by a wall of reflective Ghost hide, you may as well just detonate the engines.’

Hella said, `It’s that or be destroyed anyhow.’

Borno said, `At least we will take down a lot of them with us. Millions, maybe.’

They fell silent for a heartbeat. Then Hella called, `Pilot? It’s your decision.’

Hex knew this was a war of economics. A great deal had been invested in her crew’s raising and training, and in the ship itself. But that investment had been made to be spent. The four of them and the ship, in exchange for millions of these strange swarming new Ghosts: it was a fair price.

`It is our duty,’ she said. She brought up a bright, colour-coded display and began to work through the self-destruct procedure.

She heard Hella sigh.

Borno said grimly, `It’s been good to serve with you all.’

Jul said, `Not for long enough.’

Hex heard the tension in their voices. She had been trained for this, as for every other conceivable battlefield scenario. She knew that none of them really believed this was the end, not deep in their guts. If suicide was the only option, you did it quickly, before you had time to understand what you were doing. `I’ll set it to five seconds. Good luck, everybody.’ She reached out her gloved hand to finalise the sequence.

`Wait.’ It was a new voice, smooth, toneless, coming from her command net.

In a visual before her was a Silver Ghost. It was one of the classic sort, a perfect sphere. The image was about the size of her head, a ball of silver turning slowly in the middle of her blister.

`You hacked into our command net,’ Hex said.

`It wasn’t difficult,’ the Ghost said. Its voice, translated by the Spear’s systems from some downloaded feed, was bland, without inflection. But did she detect a trace of sarcasm?

Jul spoke, her voice tremulous with fear. `Hex? What’s going on? Just get it over-‘

`Wait,’ Hex snapped.

The Ghost said, `I will let you live, in return for a service.’

Hex could hardly believe she was hearing this. She heard the voice of her training officers in her head; in a situation like this, faced with a new stratagem by the Ghosts, it was her job to extract as much intelligence as possible. `Why us?’

`Because Aleph Force are the supreme killers in a species of killers, and you are the best of Aleph Force. Quite an accolade.’

`And what’s this “service”? You want us to kill somebody, is that it?’ A military leader, Hex speculated, a senior Commissary, maybe a minister of the Coalition’s grand councils back on Earth - Ghosts had never resorted to assassination that she knew of, but then this was a day when nothing about the Ghosts seemed predictable. `Who?’

Even on this day of shocks, the answer was stunning. `We want you to assassinate the Black Ghost.’

II

Scarcely believing what she was doing, Hex set up a conference call involving herself, her crew, her commander at the base of Aleph Force back on the Orion Line - and a Silver Ghost.

Commodore Teel, a disembodied Virtual head floating in Hex’s blister, glared at her. In his forties, Teel’s face was hard, his eyes flat, and his scalp was a mass of scar tissue. `None of you should even be alive. Pilot Officer Hex, charges aren’t out of the question.’

Hex swallowed her shame. `I know that, sir. It was a judgement call to abort the self-destruct.’

`Show me where you are.’

Navigator Hella hastily downloaded positional data to the Commodore. The Spear of Orion had been smuggled through some kind of hyperspace jump out of its cage of Ghosts and brought to a position at the rim of the system, where only icy comets swam in the dark. They were far from the fighting which still raged in the inner system.

Teel stared at the Ghost’s Virtual, which spun silently, complacently. `How did this creature bring you out here?’

Jul answered, `We’re not sure, sir. We didn’t monitor any communication between it and any other Ghost. The Ghost, um, broke us out.’

`I think we’re dealing with factions among the Ghosts, sir,’ Hex said. `Maybe there’s an opportunity here. That’s why I thought it best to pass it up the chain of command.’

`And this Ghost wants you to kill one of its own.’

`This Ghost has a name,’ the Ghost said. `Or at least a title.’

`I’ve heard of this,’ Borno sneered. `Ghosts like titles. They are all ambassadors.’

`I am no ambassador,’ the Ghost said. This is not an age for ambassadors. I am an Integumentary.’ The Spear’s systems displayed various alternative translations for `Integumentary’: prophylaxis, quarantine. `I am part of an agency that insulates humans from Ghosts, like the hide that shields my essence from the vacuum of space.’

`Charming,’ Teel said. `But, fancy title or not, you are my mortal enemy. If you want us to do something for you, then you must give us something in return.’

The Ghost spun, its flawless hide barely showing its rotation. `I expected nothing less. The one thing you wasteful bipeds relish even more than killing is trade. Bargaining, mutual deception-‘

Teel snapped, `If you expected it you have something to offer.’

`Very well,’ said the Ghost. `If you succeed we will decommission the new weapon system.’

`What new weapon?’

`Directional gravity waves on a large scale.’

The weapon that had churned up a planet. Hex held her breath.

`Download some data,’ Teel said. `Prove you can do this. Then we’ll talk.’

Hex watched, astonished, as the Spear’s systems began to accept data from the Ghost.

Every human knew the story of the Silver Ghosts, and their war with humanity.

For fifteen hundred years the Third Expansion of mankind had been spreading across the face of the Galaxy. First contact between humans and the alien kind they labelled `Silver Ghosts’ had come only a few centuries after the start of the Expansion. The Ghosts were silvered spheres, up to two metres across. Their hide was perfectly reflective - hence the human label `Silver Ghosts’; in starlight they were all but invisible.

The key to the Ghosts was their past. The world of the Silver Ghosts was once Earthlike: blue skies, a yellow sun. But as the Ghosts climbed to awareness their sun evaporated, its substance torched away by a companion star. As their world froze the Ghosts rebuilt themselves. They became symbiotic creatures, each one a huddled cooperative collective. That spherical shape and silvered hide minimised heat loss.

The death of the Ghosts’ sun was a betrayal by the universe itself, as they saw it. But that betrayal shaped them for ever. Their science was devoted to fixing the universe’s design flaws: they learned to tinker with the very laws of physics.

When humans found the Ghosts, at first two powerful interstellar cultures cautiously engaged. But the Ghosts’ home range lay between mankind and the rich star fields of the Galaxy’s Core. The Ghosts were in humanity’s way. War was inevitable.

After early quick victories, for centuries the Ghosts stalled the human advance at the Orion Line, an immense static front along the outer edge of the Sagittarius Arm. The Ghosts, capable of changing the laws of physics in pursuit of weapons technology, were a formidable foe; but humans were the more warlike.

A weapon that could use g-waves to devastate worlds was a characteristic Ghost weapon, exotic and powerful. And it worked, the Integumentary said, by tapping into the large-scale properties of the universe itself.

`Perhaps you understand that the universe has more dimensions than the macroscopic, the three spatial and one of time. Most of the extra dimensions are extremely small.’ A technical sidebar translated this for Hex as `Planck scale’. `But one extra dimension is rather larger, perhaps as much as a millimetre. You must think of the universe, then, as a blanket of spacetime, stretching thirteen billion years deep into the past and some twelve billion light years across-‘

`And a millimetre thick,’ said Hella.

`There are believed to be many such universes, stacked up’ - the translator boxes hesitated, searching for a simile - `like leaves in a book. Also our own universe may be folded back on itself, creased in the thin dimension.’

Engineer Jul said, `So what? We know about the extra dimensions. We use them when we hyperdrive.’

`But,’ said the Ghost, `your applications are not currently on the scale of ours.’

`Tell us about g-waves,’ Teel commanded.

The Ghost said that all forms of energy were contained within the `blanket’ of the universe - all save one. Gravity waves could propagate in the extra dimensions, reaching out to the other universes believed to be stacked out there. The Ghosts had learned to focus the gravitational energy raining into their own universe from another.

`The energy source in the other universe is necessarily large,’ the Integumentary said. `Alternatively it may be a remote part of our own universe, an energy-rich slice of spacetime - the instants after the initial singularity for instance, folded back. We aren’t sure. You understand that this weapon offers us a virtually unlimited source of power. It’s just a question of tapping it. Beyond weaponry, many large-scale projects become feasible.’

Hella said, `I wonder what “large-scale” might mean for a species of universe-botherers like the Silver Ghosts.’

Teel said, `Even when we were friendly with them the Ghosts scared us, I think.’

Hex had had enough of awe. `Let’s talk about the target. This weapon system is in the control of the Black Ghost …’

Recently the Ghosts had suddenly been scoring victories against the human forces. Their tactics had undergone a revolution that must reflect a change in their command structure, perhaps their very society.

`Humans work in hierarchies,’ Teel said. `Chains of command. All large-scale military organisations in the past have done so. We tend to think it’s the only way to operate, but in fact it’s a very human way to work.’

`An evolutionary legacy of your past,’ the Integumentary said. `When you were squabbling apes in some dismal forest, in thrall to the strongest male-‘

`Shut up,’ Teel said without emotion. `Ghosts, however, have always worked differently. Their organisation is more fluid, bottom-up, with distributed decision-making. The whole of their society is self-organising.’

`Like a Coalescence,’ Borno said with disgust.

`Like a hive, yes.’

`The Ghosts are this way,’ said the Integumentary, `because of our evolutionary past. As you would understand if you knew anything about the species you are endeavouring to wipe out.’

`Maybe,’ Teel said, `but you stayed that way because it’s efficient. Even in some military applications: if you’re waging a guerrilla war on an occupied world, for instance, a network of cells can be very effective. But in large-scale set-piece battles, which we always try to draw the Ghosts into, you need a command structure.’

`And now they have one,’ Hex said.

`Which makes them harder to beat. But it also makes them more vulnerable, because suddenly assassination is an effective weapon.’

Hex, intrigued, asked, `Why would any Ghost commit this treason? If the Black Ghost exists - if it lies behind these new effective tactics-‘

The Integumentary said, `The Black Ghost’s is the greater treason, because of where its project will inevitably lead.’

Teel prompted, `Which is?’

`To an arms race. Humans will steal or reinvent the gravity wave technology for themselves. Then we will conspire together, humans and Ghosts, to wreck the Galaxy between us. Or, worse-‘

`Ah,’ said Teel. `The Black Ghost will unleash such power that there won’t be anything left for the victors to take.’

`It’s possible,’ Borno said. `Ghosts are single-minded. They choose a plan and stick to it, whatever the cost.’

In the training academies there was a joke about Ghosts that had the right of way to cross a road. But the transport drivers ignored the stop signs. So the first Ghost crossed, exerting its rights, and was creamed in the process. So did the second, the third, the fourth, each sticking to what it believed was right regardless of the cost. Then the fifth invented a teleport, changing physical law to make the road obsolete altogether …

Teel said, `So you want the Black Ghost eliminated before it destroys everything. Even though this may be your best chance of winning the war and of avoiding the subjugation or even extinction that would follow.’

`Sooner extinction than universal destruction,’ the Integumentary said.

`How noble.’

Hex said, `And you, Integumentary, are prepared to make the most profound moral judgements on behalf of your whole species - and their entire future?’

Borno said, `Who cares about Ghost ethics? They won’t need ethics when they’re all dead.’

`You’re deranged, gunner, but you’re right,’ said Teel. `We don’t need to consider Ghost consciences. Our job is to consider what use to make of this strange opportunity. Certainly we need to find out more about these new Ghost variants you’ve come up against. I’ll pass this up the line to-‘

`You decide now,’ the Ghost snapped.

Borno said, `If you think a commodore is going to take orders from a ball of fat like you-‘

`Can it, gunner,’ Hex snapped.

`You decide now,’ the Ghost said again. `You allow this crew, in this ship, to follow my instructions, or I disconnect the link.’

Hella said, `I guess the Integumentary has its own pressures. Imagine trying to run a covert operation like this from our side.’

`We’ll follow your orders, whatever you say, Commodore,’ Hex said.

`I know you will,’ Teel said dismissively. `But I’ve no way of assessing your chances of success - let alone survival.’

`Our survival is irrelevant, sir,’ Jul said.

`I know that’s what you’re taught, engineer. Perhaps there are a few desk-bound Commissaries back on Earth who actually believe that. But out here we who do the fighting are still human. The mission has a greater chance of success if you’re willing to take it on.’

`I’m willing,’ Borno said immediately.

`I’ve seen your file, gunner. What about those of you who aren’t psychopathically hostile to the Ghosts and all their works?’

Hella was uncertain. `We’re flight crew. We aren’t infantry, or covert operatives. We may not be right for the job.’

`We’re Aleph Force,’ Hex said firmly. `In Aleph Force you do whatever it takes.’

`Anyhow I don’t think there’s a choice,’ Jul said. `Us or nobody.’

Hella asked, `So what do you think, pilot?’

Hex looked into her soul. A journey into the very heart of Ghost territory - a mission that might turn the course of the war - how could she refuse? `I’m in.’

Jul, Hella and Borno quickly concurred.

`I’m proud of you,’ the Commodore said.

The Ghost spun. `Humans!’

Hex snapped, `All right, Ghost, let’s get on with it. Where are we going?’

More data chattered into the Spear’s banks.

III

The Spear of Orion swept through space. The needleship moved from point to point through hyperdrive jumps, each too brief for a human eye to follow, so that the stars seemed to slide through the sky like lamp posts beside a road. For the crew the journey was a routine marvel.

But Hex and her crew had come far from the outermost boundary of human space, farther than any human had travelled from Earth save for a handful of explorers. And every star they could see must host a Ghost emplacement: if humanity was turning the Galaxy green, then this rich chunk of it still gleamed Ghost-silver. But the Spear remained undisturbed.

`It’s eerie,’ engineer Jul said. `Ghosts should be swarming all over us.’

Hex said, `The Integumentary promised to make us invisible to the Ghosts’ sensors, and it’s keeping its word.’

Jul, a practical engineer, snorted. `I’d feel a lot more reassured if I knew how.’

Borno said, `What do you expect? Ghosts don’t give you anything.’ His pent-up rage, here in Ghost territory, was tangible.

They sailed on in tense silence.

Borno had been born between the stars. His ancestors, who called themselves `Engineers’, had fled Earth at the time of an alien occupation. With no place to land the refugees had ganged together their spacecraft and found ways to live between the stars, through trading, piloting, even a little mercenary soldiering.

When the Third Expansion came, Borno’s Engineers had been one of a number of peripheral cultures recontacted by the Coalition, the new authority on Earth. But the Engineers had also forged tentative links with the Silver Ghosts, who were undergoing their own expansion out of the heart of the Galaxy. For a time the Engineers had profited from trade between two interstellar empires. They even welcomed small Ghost colonies on their amorphous islands of relic spacecraft and harnessed asteroids.

But then Navy ships came spinning down to impose Coalition authority on the Engineers’ raft culture. There had been a strange period when autonomous Ghost enclaves had been granted room to live under the new regime: Silver Ghosts, living under Coalition authority. But the Ghosts had been taxed, marginalised and discriminated against until their position was untenable. Their maltreatment had led to a rescue mission from Ghost worlds - and that had led to one of the first military engagements of the long Ghost Wars, fought out over the Engineers’ fragile raft colony. Among the Engineers, many had died, and the rest had been dispersed to colonies deeper within Coalition space.

All this was centuries ago. But Borno’s people had never forgotten who they were and where they had come from; they still called themselves `Engineers’. And in their minds it had been Ghost aggression that had resulted in the deaths of so many and the loss of an ancient homeland.

Hex reflected that it would do no good to try to explain to Borno that it had been Coalition policy that had precipitated that defining crisis in the first place. And besides, Borno’s wrath was useful for the Coalition’s purposes. In a war that spanned the stars, he was not unique.

`Heads up,’ Hella said. `I have a visual. Theta eighty-six, phi five.’

Their destination was dead ahead.

Hex saw a double star: a misty sphere that glowed a dull coal red while a pinpoint of electric blue trawled across its face.

The Spear’s crew had had to find their way here by dead reckoning. This system didn’t show up in the Navy’s data banks. After fifteen centuries of the Third Expansion, the Commission for Historical Truth believed it had mapped every single one of the Galaxy’s hundreds of billions of stars, human-controlled or not - but it hadn’t mapped this one.

Anomaly or not, somewhere in this unmapped system, the Integumentary had promised, the crew of the Spear would find the Black Ghost.

Gunner Borno said hastily, `We’re crawling with Ghosts.’

Hex checked her displays. All around her were Ghosts: their ships, their emplacements, their sensor stations and weapons platforms. The whole system was like a vast fortress, defended to a depth of half a light year from that central double sun, with more monitoring stations and fast-response units even further out.

`None of them are reacting,’ Jul said, sounding disbelieving. `Not one unit.’

Hex said, `Then forget them. What are we looking at?’

Jul said, `I’ve seen systems like this before. That blue thing is a neutron star, right?’

`Yes,’ Hella said, `Actually a pulsar …’

Once this had been a partnership of two immense stars - until the larger, too massive, had detonated in a supernova explosion, for a few days outshining the whole Galaxy. Its ruin had collapsed to form a neutron star, a sun-sized mass compressed down to the size of a city block. As it spun on its axis a ferocious magnetic field threw out beams of charged particles to flash in the eyes of radio telescopes: it was a pulsar.

As for the supernova’s companion, the tremendous detonation stripped away most of its outer layers. Its fusing core, exposed, had not been massive enough to maintain the central fire. The remnant star had subsided to misty dimness.

Hella said, `But the system is actually still evolving. That pulsar is dragging material out of the parent.’ She displayed a false-colour image that showed a broad disc, material the pulsar’s gravity had dug out of the larger star’s flesh and thrown into orbit.

`So that star blew its companion up,’ Borno said, `and now it’s taking it apart bit by bit. What a dismal place this is.’

`And yet,’ Hella said, `this system has planets. Two, three, four - more off in the dark, they surely don’t matter. It’s the innermost that has the most Earthlike signature: air, liquid water, oxygen, carbon compounds. Smaller than Earth, though.’

Across human space people always spoke of Earthlike worlds, though few of them had ever seen Earth; the mother planet remained the reference for all her scattered children.

The original binary could have hosted Earths, if they were far enough from the brilliance of the central stars. No biosphere could have survived the supernova detonation, but once the system became stable again, any surviving worlds could have been reborn. Comets or outgassing could create a new atmosphere, a new ocean. And life could begin again, perhaps crawling out of the deepest rocks, or brought here by the comets - or even delivered by conscious intent; this was a Galaxy crowded with life. How strange, Hex thought, a planet that might have hosted not one but two generations of life. She wondered if its new inhabitants had any idea of what went before - if those doomed by the supernova had managed to leave a trace of their passing, before being put to the fire.

`But that pulsar is still chipping away at the red star,’ Jul said. `The sun is failing.’

`And if there are Ghosts here they are suffering.’ Borno snarled. `Good.’

Hella called, `There isn’t much off-world, but I can see one large habitat orbiting the innermost planet.’

`Then that’s our destination.’ Hex set up an approach trajectory. She felt the needleship’s intrasystem engines thrumming around her, powerful and secure, and the dim red sun swept towards them.

Borno said, `Pilot, your trajectory will take us right through the thick of the Ghosts.’

`Gunner, they either see us or they don’t. We may as well walk in the front door.’

Borno said tensely, `Trusting a Ghost with our lives?’

`That’s always been the deal.’

`You mean,’ Jul said, `the whole mission’s always been halfassed. ‘

`Stay focused,’ Hex murmured.

`Closest approach,’ Hella called now.

The star ballooned out of the dark. Its dim photosphere bellied beneath Hex’s blister, churning dully, disfigured by huge spots. A pinpoint of electric blue rose over the crimson horizon of the parent, casting long shadows through the columns of glowing starstuff that its gravity hauled up from the body of the parent star.

`Sunrise on a star,’ Borno said. `Now there’s something you don’t see every day.’

`But we’ve got more anomalies,’ Jul reported. `The parent’s composition is all wrong. Too much hydrogen, not enough metals. Younger stars incorporate the debris of earlier generations, fusion products, heavy elements like metal, carbon. It’s as if this star is too old - only by a million years or so, but still-‘

`I’ll tell you something stranger,’ Hella said. `This star system may not be in the Coalition catalogues, but it’s a near-identical twin of a system that is.’ She brought up an image of another system, another red star with a bright blue companion pulsar; Hex saw from the accompanying data that the system’s orbital dynamics were virtually identical. Hella said, `This other star is in Ghost space too. Only a few tens of light years away.’

Hex let all this wash through her. You weren’t wise to block information flows, especially when you were flying into the unknown like this. But she couldn’t see an immediate relevance in these stellar mysteries.

She was relieved when the twin stars fell away, the needleship climbed back out of the parent star’s gravity well, and the target planet came looming out of the dark.

Unlike the rest of her crew Hex had been brought up on a planet, only a few light years from Earth itself. But even to her eyes this little world looked strange. Huddled close for warmth, it kept one face to the parent star. The subsolar point on the daylight hemisphere, where the sun would be perpetually overhead, must be the warmest place on the planet. Hex made out climatic bands of increasing dimness sprawling around that central point, so that the face of the planet was like a target, bathed crimson red. And on the dark side, illuminated only by starlight, she glimpsed the blue tint of ice.

As the needleship swung closer, she made out more detail on the sunward side: dark patches that might have been seas, broad crimson plains, and here and there a bubbling grey that was the characteristic of habitation, cities. But sparks crawled over the terminator, the boundary between day and night, and where they landed fire splashed.

Jul murmured, `What are we getting into here? It looks like a war between the day and night sides.’

Hella said, `That big orbital habitat is by far the highest technology on or around the planet. The materials, the trace radiation - it looks like it’s the only example of modern Ghost technology here.’

`If the Black Ghost is anywhere,’ Hex said, `that’s where it will be. Fix the course, navigator-‘

The Spear shuddered and spun crazily, that faint sun and its huddled world whirling like spectres. Hex’s blister lit up with alarm flags, flaring bright red.

She barked out commands and wrestled with her joystick. `Report!’

`It was g-waves,’ Jul called back. `Just like the beams they used back on 147B.’

`Were we targeted? They aren’t supposed to be able to see us.’

Hella said, `The whole system is crisscrossed by the beams. We just ran into one.’

`A defensive measure?’

`I don’t know. Maybe. Or something to do with the stellar system itself-‘

Borno said, `We have company. Theta thirty, phi one hundred. They are coming out of that habitat.’

A swarm of palette-ships came swooping down on the Spear. Maybe it had been too much to expect the Integumentary’s shielding to survive the g-wave buffeting.

Grimly Hex fought with the still-spinning ship. `Open up the weapons ports.’

`Half of them are off-line,’ Jul called back. `And our sensors are blitzed too. Right now we’re de-fanged, pilot. Give me two minutes and-‘

The first shot sizzled through space only a couple of kilometres from the Spear’s nose.

`We don’t have two minutes,’ Hex snapped. `Options. Come on, guys!’

`Fight!’ Borno called.

`Run,’ said Jul.

`Abort to the planet’s surface,’ advised Hella.

At last Hex got the spin under control. But the face of the planet was a mottled crimson shield before her. More alarms lit up as the needleship sensed the first touch of this world’s thin atmosphere. `Looks like we don’t have much choice.’ She hauled on her controls, turned the needleship so its nose pointed down into the atmosphere - and she lit up the intrasystem drive to hurl the ship into the cover of air. A ball of light engulfed the Spear, atmospheric gases ionised and driven to white heat. In the blisters the inertial control held, more or less; Hex and her crew felt only the mildest of judders as they fell into the air of an unknown world.

All this in utter silence.

`We’re kind of lighting up the sky here, pilot,’ Borno called.

Hex said, `It will get us down quicker. The ground proximity sensors will pull us out before-‘

`Sensors are off-line,’ Jul reminded her hastily.

`Oops,’ said Hex. She hauled on her joystick.

`Land below us,’ Hella called. `Now over ocean-‘

Hex’s blister filled up with crash foam, embedding her like a wrapped-up doll, so tight she couldn’t move a finger. She felt nothing as the Spear of Orion cut a tunnel through an ocean a half-kilometre deep, and then, before the waters had even closed, gouged a crater fifty kilometres across in the soft rocks of the ocean floor.

Her crash foam shattered, broke up and fell away.

She was floating. She was surrounded by misty grey-green air, illuminated by dim slanting light - no, not air, she realised as she tried to move her limbs. This medium was water. Thankfully her skinsuit was holding.

She looked around. Flecks of her crash foam fell away. Of the needleship, her crew, there was no sign in this murky soup. The Spear of Orion had been her first command, and now it was gone in seconds.

And here she was, immersed in an unknown sea. Hex’s world was largely untamed. Her people, like humans everywhere, were drawn to the sea, but you never went swimming, for the ocean was full of monsters. She didn’t even know how deep she was - or which way was up. For a moment panic bubbled, and she thrashed, wasting energy, until she forced herself to be still.

She ordered her skinsuit to use the planet’s gravity field to find the local vertical. Then, when it was oriented, she made the suit climb. She glimpsed the ocean’s scummy meniscus an instant before she broke through into the air, to her huge relief.

She rose into a crimson sky, where a misshapen sun hung low. Beneath her the ocean looked black, oily, and huge, languid low g-waves crossed its surface. But she could see, deep down beneath the waters, a pale pink glow that must be the crater they had made.

Another skinsuit broke the surface, popping up like a balloon. Then a third, and a fourth. Hex made them sound off and report on their status. Everybody was unscathed, physically anyhow. They bobbed over the surface of the ocean, four drifting people in bright green suits.

`The Spear has had it,’ Jul said. She downloaded to Hex a last data squirt from the dying ship.

`We’re stranded,’ Hella said gloomily.

`We still have weapons in our suits,’ Borno said.

Hex said, `If we can find anybody to shoot at.’

Jul pointed down at the ocean. `Pilot - what’s that?’

Something moved, just under the surface. Larger than a human, amorphous, dimly glimpsed, it seemed to be moving purposefully.

Hex could hear her mother’s voice: There are monsters in the sea. `My turn to be phobic,’ she murmured.

Hella said, `What? … Look. It’s breaking the surface.’

Hex glimpsed sleek flesh humping above the water. Then something like a limb protruded. Hex flinched; it was as if the limb had reached for her.

`I can’t make out its shape,’ Borno said.

`Maybe it has no fixed shape,’ Hella said. `I’ve read some creatures of the seas are like that.’

`But it’s a toolmaker,’ Jul said calmly. She pointed. `It’s wearing a kind of belt.’

All this seemed utterly horrific to Hex. That limb, muscular, equipped with suckers and fine manipulators, continued to writhe in the air.

`You know,’ Hella said, `I think it’s beckoning.’

`To us?’

`Of course to us. I think it wants us to follow it - to the land, probably.’

`What land?’ Jul asked.

Hella sighed. `Some navigator you would make. Over there.’

There was a dark shading on the horizon.

Hex’s sharp pilot’s eyes picked out sparks descending from the sky. `We’re out of time.’

`They’re tracking the wreckage of the ship,’ Jul said.

`We stand and fight,’ Borno snarled.

`Not here,’ Hex snapped. `Not now. Borno, we can’t win.’

`We should follow the swimming thing,’ Hella said. `It might help us.’

`You think so?’ Jul asked.

`It’s clearly smart. And it’s trying to help us right now. Why not?’

Hex looked down with huge reluctance at the blank surface of the water, the uncharted depths beneath. `We don’t have a choice,’ she told her crew, and herself.

She flipped in the air and plunged head-first back into the water. Her suit’s systems whirred as it sought neutral buoyancy, and made her legs kick. Her tell-tales showed her that her crew followed her in: one, two, three.

They all struggled through the water in pursuit of the `swimming thing’.

IV

Hex woke. She was reasonably comfortable, even warm. But when she looked up, she peered out through a translucent bubble-wall at the roof of a cave.

She stretched, sat up.

By the light of a suit lamp, the others were already eating. They sat around suit backpacks that glowed green, giving off light and warmth. Breakfast was a slab of sticky, green, manufactured by a backpack from the organic produce of this world’s ocean, washed down by a visor-full of water.

On staggering into this sea-shore cave Hex had inflated her own suit to form this bubble-tent. If you looked carefully you could see the suit’s seams, even one stretched-out glove. Inside, the crew had stripped off their suits, pooled their backpacks, and slept, lying on one stretched-out suit while blanketed by another. They had needed time for some essential maintenance, of themselves as much as their suits.

In the mouth of the cave, beyond their shelter, a fire burned fitfully, hampered by poor convection in the low gravity. Oddly the flickering glow of the fire seemed more human than the pale green of the suit lights, but it had been built by an utterly alien being.

It was odd for Hex to have her crew together like this. She had spent most of the last year with them, but for most of their time together they were sealed up in their blisters. Now here they were, stripped down to their heated undergarments, all crammed in. Borno, the only man, was bulky, big-boned, hard-muscled. She imagined him spending hours honing his body so he could take down Ghosts hand on hand if he had to. Hella was smaller, thin, morose and anxious, but possibly the smartest of the three. Jul looked a little overweight; maybe she had been skimping physical exercise. Of course the fact that the lower half of her body was a clunky prosthetic didn’t help.

And then there was Hex - the youngest, she uncomfortably reminded herself.

Borno groused, `We’re interstellar warriors and we’re reduced to this. Stuck in a cave like animals. You can’t even tell if it’s morning or night.’

`It’s always day here, dummy,’ Hella said. She sounded tired, drained; she chewed on her food tablets without enthusiasm.

`Lethe, you know what I mean. It’s morning somewhere …’

Restless, Hex made her way to the wall of her suit-tent. They were in the northern hemisphere, but the cave was oriented south, so she could see the twin suns, a glum red blur with that spark of bright blue crawling over its face. It was strange to think that the double star never moved from its station in the sky, as if nailed there. The ground was worn, a thin soil lying over the melted bedrock that was all that had survived a supernova torching. The air was less than a fifth Earth’s pressure: too thin for them to breathe, but enough to transport sufficient heat around the planet to keep all the water, and indeed the air itself, from freezing out on the dark side.

And on this small world, in this thin air, there was life.

Hex made out gaunt silhouettes standing on a low ridge. They looked like antennae, with dishes turned up to the sun. They were plants, something like trees - but they were colony organisms, with the leaves independent creatures, roosting on the branches like birds. The pool of shadow behind that ridge hadn’t been touched by sunlight for a million years.

`We’ve got company,’ Hella murmured.

A puddle of slime, glistening in the low sunlight, flowed in over the cave floor. It gathered itself up into a rough pillar and let fall a belt stocked with tools of stone and metal. Unstable and oozing, it seemed to warm itself by the fire, and pseudo-pods extended to hurl a little more fuel onto the flames. Then it collapsed again and came slithering over the floor of the cave towards the humans’ shelter. It dumped organic produce by the translucent wall: what looked like seaweed, and even a fish, a triumph of convergent evolution.

This was the crew’s only ally on this strange world.

His name for himself had translated as Swimmer-with-Somethings, the `somethings’ being an aquatic creature they hadn’t been able to identify. Close to, he looked disturbingly like a flayed human, immersed in a kind of gummy soup within which smaller creatures swam. The `he’, of course, was for the crew’s convenience, though there might have been genders among the myriad creatures that made up this composite animal.

The motile puddle pushed a membrane above its oily meniscus, and Hex heard soft gurgling sounds.

Hella studied her suit’s translator box. `He says-‘

`Let me guess,’ said Hex. ` “More food.” Tell him thanks.’ She meant it. The humans couldn’t eat the native life, but the biochemistry was carbon-based, and their suits’ backpacks were able to use this raw material to manufacture edible food and to extract water.

Hella murmured into her unit, and the membrane pulsed in response. They had been surprised how easy it had been to find a translation. Swimmer’s speech pattern was similar to some variants of the Ghost languages which humans had been studying for centuries, an odd fact which Hex had filed away as one of the many puzzles to be resolved about this place.

Engineer Jul was fascinated by the creature’s biological organisation. `Look at that thing. He’s obviously a colonial organism. Every so often all the components go swimming.’ She pointed. `Those little blobs look like algal cooperatives. Powered by capillary action, probably. But these “algae” are jet black - probably something to do with the photosynthetic chemicals used in the local ecology. I’m not sure what those little swimming shrimp-like creatures are for …’

Swimmer had a skeleton of something like cartilage, and `muscles’, pink and sinewy, adhered to it. But the cartilage itself was independently mobile. And now a `muscle’ detached itself from its anchor, swam to the surface of the slimy pool into which Swimmer had deliquesced, and opened a mouth to breathe the air.

Borno’s face contorted. `How gross.’

`More gross than a Ghost?’ Hex asked.

He turned to her, his eyes stony. `Well, now, that’s the question, isn’t it? We know the Ghosts are some kind of colony creature too. And we know that this wriggling, dissolving thing speaks a kind of basic Ghost language. I think it’s time we asked him what is going on here - and what he has to do with the Ghosts.’

`He may not know,’ Jul warned. `He is technological, but primitive. And we may turn him against us.’

Borno snapped, `So what?’

`I think Borno’s right,’ Hella said. `We’re not getting anywhere sitting in here. We have to take a few risks.’

`If he knows who’s shooting at him from the nightside,’ Borno said, `it would be a start.’

Hex considered. She had been trained by the Commissaries in alien psychology - or at least, how to manipulate it. `We humans are very self-centred,’ she said. `Everything revolves around us. But for Swimmer, we’re peripheral. He doesn’t care what we want, even where we came from. He’s helping us stay alive for his own reasons - and that’s our angle. Hella, try asking him why he’s helping us.’

Hella murmured into her translator unit.

He was helping them, Swimmer replied, because they were the enemies of his enemies.

Swimmer didn’t know that the ecology that had spawned him was the second to have arisen on this battered world.

His sun was dark and cold to human senses, but to the creatures that evolved in its ruddy light it was a warm steady hearth. `In fact,’ Hella said, smiling, `Swimmer doesn’t believe that life on a planet like Earth is possible. A dazzling sun, a daily cycle of light and dark, seasons, ice ages - how could any ecology evolve in such a chaotic environment?’

Life here, though, had taken a different route to Earth. The continued cooling of the sun had exerted a selective pressure to huddle, to share, to keep warm. Here large animals were rare, cooperative organisms the norm.

Hex had never seen another of Swimmer’s kind, but it seemed he joined with others in the depths of the sea. There the bits that made up the people danced in their own eager matings. And if you came out of the great merging with a slightly different set of subcomponents, so what? Hex suspected that `identity’ meant something rather different to these people than to her own.

When intelligence evolved among Swimmer’s predecessors, their biology shaped everything they did. Unlike humans their politics was a matter of cooperation rather than competition, though there could be disagreements, even wars. They crawled out onto land - surely the low gravity helped them with that conquest - where there were raw materials to be shaped, power sources like fire impossible under water. Their different origins shaped their technology. They discovered a genius for moulding themselves and their coevals; these people were capable of advanced biochemistry, though their physical technology was no more than Iron Age.

They had even managed to achieve spaceflight. A handful of Swimmer’s people cloaked themselves in a new kind of hide, a tough, silvered skin capable of retaining inner heat while resisting the harsh radiations of space. In time ice moons and comet nuclei had become home to a new variant of Swimmer’s kind, who rarely visited the home planet.

But all the while the pulsar continued its slow, lethal work of slicing away the substance of the sun.

As this story unfolded, the Spear crew exchanged glances of recognition.

It had become increasingly clear that a crisis was approaching. A decision emerged from the interconnected councils of the people. The interplanetary wayfarers were summoned home. The most technologically advanced of their kind, perhaps they could find a way to save the world.

The space-hardened wayfarers returned. By now the ice cap on the nightside, hard and cold, was not so different a habitat from the ice moons they had made their home. But they found they resented being begged for help by those they regarded as a primitive, weaker form. They saw ways to use this fat rocky world for their own purposes - and all the better if the murky atmosphere and muddy oceans were frozen or stripped off.

Bringing the spaceborne home was a catastrophic mistake. They had diverged too much from Swimmer’s kind. There were two species now, too far apart, competing for the same space. Conflict was inevitable.

The nightsiders were outnumbered by the daysiders, but were far more technologically advanced. For centuries they had been launching missile after missile over the terminator, from the dark to the light. At first the daysiders had fought back; epic invasions of the night had been launched. But as its cities and farms were devastated, the thin material base of the dayside crumbled. By now only scattered survivors, like Swimmer, remained. They mounted guerrilla actions against nightside patrols. But they knew the war was lost, and their future with it.

And recently, as if they had not suffered enough, a new peril had arisen, when a new light crossed the sky.

`The habitat of the Black Ghost,’ Borno said grimly.

Suddenly the simple ships of the nightsiders had been equipped with faster drives and still deadlier weapons. Swimmer, with a resigned acceptance, had come to believe that his people’s time was up - until, in the form of the humans, he had stumbled on his own miracle from the sky.

Hex was distracted by a shadow crossing the cave mouth.

Hella was growing excited. `Pilot, I think I’ve figured it out-‘

`Shut up,’ Hex hissed. The shadow crossed again. Now she was sure: it was a palette-ship, and four, five, six Ghosts, angular rhomboids, rode it menacingly. Hastily she shut down their packs, and made her crew lie flat. Even Swimmer lay still in his puddle of slime.

The palette paused briefly at the cave mouth, but anything within was hidden by the fire. With a careless burst of an energy weapon the Ghosts smashed Swimmer’s hearth, scattering its fuel. Then the palette moved on.

The crew stood up cautiously.

Borno said, `So they’re looking for us. We have to get out of here.’

Hella grabbed his arm. `Not before you listen to me. I’ve worked it out. This world is-‘

`The home world of the Ghosts,’ Borno said, dismissively. `And this is their origin, from a million years back or so, somehow brought forward in time. Isn’t that obvious?’

Not to Hex. Her jaw dropped; she deliberately closed it.

Jul was figuring it out too. `Yes, yes. Swimmer speaks a variant of one of their languages. Ghosts are cooperative organisms, just like Swimmer. Even their hides were once independent creatures-‘

`Every Ghost is a whole ecology in a sack,’ Borno murmured, repeating training-ground lore.

Hella said, still excited, `We even found a copy of this system thirty light years away! That must be the present-day copy - this one is dredged up from the past …’

Jul said, `The “primitive” Ghosts must come from this world. The Black Ghost recruited them here.’

`Maybe that’s why this was done,’ Borno said darkly. `The Black Ghost has tapped its own deep past for raw material for the war with humans. When Ghosts told us about their origin they never mentioned this devastating civil war, did they? Funny, that.’

Hella turned to Hex. `Pilot? You’ve been very quiet. What are you thinking?’

Hex looked at her, abstracted. `About time travel.’ Humans had achieved time travel, of course. Every faster-than-light ship was a time machine, and it was said that in the old days the legendary hero Michael Poole once travelled through time in a wormhole. `We’ve sent a few people, a ship or two, through a few centuries. But the Ghosts have brought a star system, a whole system, up through a million years.’

That sobered them.

Jul said, `The Integumentary did say that their new extra-dimension technology was opening up vast energy sources for them.’

`Yes. But I never dreamed it would be capable of something like this.’

`And,’ Borno said coldly, `it’s in the hands of the Black Ghost.’

`So we have to stop it,’ Hex said. The others nodded, determined.

`All right,’ Hella said. `But how? We’re still stuck in this cave.’

`We have to get off the planet,’ Hex said. `And as far as I know the only launch capabilities are the nightsiders’.’ She considered Swimmer. She wondered if he knew he had been projected into the farthest future of his own kind. `Hella, do you think your new friend could help us get across the terminator?’

V

Under the guidance of Swimmer-with-Somethings, they journeyed north. They would cross into night somewhere near the planet’s spin pole.

The journey took them days - Earth days. They travelled out of sight of the ur-Ghosts, as they took to calling them, these cousins of Swimmer hardened for space but not yet of the optimal spherical form they would reach later. They clambered through tunnels, along the shadowed floors of deep ravines, and swam under the sea, their suits’ inertial control packs labouring to keep up with Swimmer’s economical motions. When they stopped, while the humans tended their blisters, Swimmer huddled in a gelatinous mass in any sunlight he could find, or, if they were in the ocean, he discorporated with exuberant relief. It was a mystery to Hex how the little shrimps and algae and amphibians that made up his body knew when to come back, and how to reintegrate.

As they forged steadily north the sun slid down the sky, and the shadows stretched long and deep. In the dimming sky Hex glimpsed stars, and the single bright pinpoint, steadily tracking, that was the Black Ghost’s habitat.

At last they came to a place where the sun sat on the horizon, glowing like hot coal. It looked as if it was about to set, but of course it never would. Life was sparse at this high latitude. An analogue of grass spread across the ground, though its native photosynthetic chemicals made it black, not green. But nothing grew in the long shadows, on this world where every shade was permanent.

Swimmer left them here. Unable to tolerate freezing temperatures, he could go no further. `Fight well for me,’ he said to them through Hella’s translator box. Then he squirmed away, like rainwater disappearing down a drain.

Hex looked north into the darkness. She saw motion: palette-ships, patrolling this boundary between day and night.

Borno pointed. `There are structures over that way.’

`Let’s get on with it,’ Hella said tautly.

Following Borno’s lead, they walked into the night. Hex could sense Jul’s fear, Hella’s tension, and Borno’s grim, bloody determination.

The sun disappeared altogether. They passed a few last trees, so tall that their leaves blazed in sunlight while frost gathered on their roots. `Interesting bit of biomechanics,’ Jul said nervously. `They must have evolved to exploit the temperature differences between their crowns and their roots. And I guess these last trees must be as tall as this stock can grow, otherwise-‘

`Shut up,’ Borno hissed.

They came to a wall. It was just a heap of what looked like sandbags, glowing silvery in the dim light. They crouched behind this and cautiously peered at the structures that lay beyond.

Hex saw a kind of city, spun out of silver and ice, resting on a black velvet landscape. Necklaces swooped between cool globes, frosted, icicles dangling. Sparks of light drifted between silvered domes: Ghosts, or ur-Ghosts. The place had an organic look, as if it had been grown here rather than planned. But there was nothing of Swimmer’s vibrant, swarming physicality to be seen in this chill place.

This was a typical Ghost colony. Ghosts stayed away from the heat of stars, but they had remained planet-dwellers; they tapped a world’s geothermal heat for their energy, just as they evidently had on this, their own freezing world. And their colonies always had this tangled, unplanned look.

There were anomalies, though. On a slim spire that towered over the reef-city, a light pulsed steadily, brilliant electric blue. And at the very centre of the township a squat cylinder brooded. Hex’s suit sensors told her this was merely the upper level of a complex dug deep into the ground, where thousands of Ghosts swarmed. This fortress, very unlike Ghost architecture, was the work of the Black Ghost, obvious even here, just inside the boundary of night.

Borno tapped Hex on the shoulder and pointed.

A handful of ur-Ghosts swarmed around a palette-ship on the ground. The Ghosts’ forms were variants of parallelepipeds, like slanted boxes. They were really quite beautiful, Hex thought, their facets flashing like mirrors in the starlight as they worked.

Borno whispered, `Four of them, four of us. We can take them out. And then we can grab that palette-ship and get to orbit.’

Jul hissed, `We only just crossed the terminator. Maybe we should go further before-‘

`What’s the point? We came here to find a way off the planet. There’s our opportunity.’ He raised his hand, holding a knife.

Hex said, `Borno is right. The longer we hang around the more chance we have of getting caught. Let’s do this. There’s a blind side over there, to their right. Borno, if you take Jul and head that way, Hella and I can-‘

Hella cried, `Look out!’

The wall behind Hex’s back suddenly gave way, and she was tipped onto the cold ground. When she looked up she saw that the `sandbags’ were suspended in the thin air, heavy, rippling sacks swarming over her head. There must have been fifty of them, more.

This `wall’ had a been a reef of ur-Ghosts, huddled together. She should have known, she thought; she had seen their space-filling antics in combat. What a stupid mistake.

The ur-Ghosts descended.

Borno screamed, `Weapons!’ Snarling, his blade in his hand, he was trying to get to his feet.

Hex raised her arms. Her suit weapons powered up.

`Don’t fire.’

The ur-Ghosts went limp, quivered, and fell. It was like having sacks of water dropped on you from a height. Hex’s suit turned rigid to protect her. Then the crew of the Spear fought their way out from the heap, shoving the floppy sacks away with a whir of exoskeletal multipliers.

Beyond this chaotic scene a Ghost hovered, bobbing gently with a delicacy that belied its mass. It was one of the modern kind, a smooth, seamless sphere. Borno raised his blade, but Hex grabbed his arm.

`You are the Ghost we met. The Integumentary. You’ve dogged us all the way.’

`Yes. From one blunder to another. I am here to ensure the success of the mission. I hoped I wouldn’t have to reveal myself; I hoped in vain. I never believed you would be so stupid as to hide behind a stack of warriors.’

Jul looked around at the limp ur-Ghosts that lay like immense raindrops on the ground. `Why do they cluster like this? You don’t.’

`Perhaps it’s a relic of their past,’ Hella said. `Swimmer congregated with his kind. These strange forms long to do the same.’

`Now they know you are here,’ the Ghost said. `The Black Ghost and his hierarchy. They know I am here. You have little time. I suggest you hurry to the transporter you chose.’

They clambered past the heaps of fallen Ghosts and ran.

The four ur-Ghosts who had been tending the palette-ship had fallen like the others. When Borno reached the first of the ur-Ghosts he raised his knife, preparing to cut into its hide.

`It is dead,’ the Integumentary said quickly. `I had to kill it. I had to kill them all.’ It hovered over the fallen ur-Ghosts, its movements agitated.

Borno, his knife still raised, laughed. `You killed your own kind, dozens of them, to aid an enemy that is determined to eradicate your species. You really are screwed up, Ghost.’

`I serve a cause beyond your comprehension.’

`Oh, really? Comprehend this.’ Borno plunged his knife into Ghost hide. A watery fluid, laced with red blood, spilled out onto the cold ground.

`I told you it is dead,’ said the Integumentary.

`I know,’ Borno said. With an effort he ripped back the ur-Ghost’s skin, exposing glistening muscles, organs. `Pilot, we can ride this ship up to orbit, but do you think the Black Ghost will let us just sail in? We’ll wrap ourselves up in this stuff. Camouflage. Come on, help me.’

Jul said, `That’s repulsive.’

Borno shrugged and carried on cutting.

Such an unsophisticated ploy would never work, Hex thought. But maybe they could use a little psychology, let the Black Ghost think it had won a victory. She stepped forward, chose an ur-Ghost of her own, and took her knife from its sleeve on her leg. `Let’s get it over.’

The Integumentary spun, agitated. `You humans are beyond understanding.’

`Which is why you hired us to do your dirty work,’ Borno snapped, contemptuous.

As she worked Hella said, `Integumentary - what is that?’ She pointed at the tower that rose from the Ghost city, with its electric-blue light pulsing at its tip.

The Ghost said, `You understand where you are, what world this is. In these times, my ancestors understood full well that it was the pulsar that was destroying their sun. So they venerated it. They made it a god. They called it-‘

Hex’s translator unit stumbled, and offered her a range of options. Hex selected Destroyer.

Hella said, `Fascinating. Humans have always worshipped gods who they believed created the world. You worship the one that destroyed it.’

`It is a higher power, if a destructive one. It is rational to try to placate it. All intelligent creatures are shaped by the circumstances of our origins.’

Borno sneered. `It’s terrible for you to be brought here, isn’t it, Ghost? To confront the darkest time of your species. You’d prefer to believe it never happened. And now humans are learning all about it.’

The Ghost spun and receded. `You haven’t much time.’

Borno had already got the skin off his ur-Ghost. An independent entity in its own right, it was flapping feebly on the cold ground, and the ur-Ghost’s innards were creatures that flopped and crawled. Borno kicked apart the mess with a booted foot.

VI

The cup-shaped indentations in the surface of the palette-ship were just shallow pits. Hex had to sit cross-legged.

Borno set up an ur-Ghost hide over her, like a crude silvered tent. Hex was sealed in the dark. The hide, freshly killed, was still warm, and she felt blood drip on her back. But she shut her suit lamp down, set her visor to show her the exterior of the ship, and tried to forget where she was.

The palette-ship turned out to be simple to operate. After all, analysts in military labs had been taking apart Ghost technology for generations. All Hex had to do was slap her gloved palms flat against the palette’s hull, and her suit found a way to hack into its systems. Experimentally she raised her arm. The palette lifted, tipped and wobbled, a flying carpet on which they were all precariously sitting. But then the inertial control cut in properly, interfacing with their suits’ inertial packs, and she felt more secure.

`Some ride this is going to be,’ Borno said.

`Yes, and then what?’ Jul snapped.

`We’ll deal with that when it comes,’ Hex said. `Have your suit weapons ready at all times.’

`I think we’d better get on with it, pilot,’ Hella murmured.

Hex, through her visor’s systems, glanced around. She was a hundred metres above the ground, and the Ghost city was laid out beneath her, a chaotic tangle of silver cables. She could still see the bloody smears that were all that was left of the ur-Ghosts they had skinned. And silvery sparks were converging.

Hex called, `Everybody locked in? Three, two, one-‘ She raised her arm again, and the palette shot skywards.

From space the extent of the ur-Ghosts’ betrayal of their cousins was clear. Their chrome-dipped cities clustered over every scrap of land, with only the ghostly blue-white of the ice cap left untouched. No wonder this terrible fratricidal episode was expunged from the Ghosts’ racial memory.

`Pilot,’ Hella whispered. `The habitat. Theta ninety, phi twenty.’

Hex looked ahead. Riding high above the icy nightside clouds a structure was rising. At first glance it looked like typical Ghost architecture, a mesh of silver thread. But Hex made out a darker knot at the centre of the tangle.

So this was the bastion of the Black Ghost. It was no more than a kilometre away.

`End game,’ Borno said softly.

`Let’s move in.’ Hex raised her arms, and the platform slid forward.

Suddenly palette-ships came rushing out of the tangle like a flock of startled birds.

Jul cried out, `Lethe!’

Hella said tightly, `They’re going around us, pilot. Hold your line. Hold your line!’

Hex ground her teeth, and kept her hands steady as a rock. The fleet swarmed around her and banked as one, swooping down over the limb of the planet.

`You’ve got to admire their coordination,’ Hella said. `I’ve never seen Ghost ships move like that.’

`That’s the influence of the Black Ghost,’ said Borno.

`They’re heading for the dayside,’ Jul murmured. `Swimmer and his people are going to get another pasting.’

Hex said firmly, `Then let’s see if we can put a stop to it.’

They covered the remaining distance quickly.

The palette slid into the habitat, among threads and ducts; it was like flying into the branches of a silvered tree. Though individual ur-Ghosts slid around the inner structure, nothing opposed them.

Soon the clutter of threads cleared away, and the big central bastion was revealed. It was a sphere, black as night, kilometres across. In the jungle-like tangle of Ghost architecture it didn’t fit; it was alien within the alien.

`That wall is a perfect absorber of radiation,’ Jul called. `A black body.’

`You see what this is,’ Borno brayed. `The Black Ghost built its central bastion in its own image. What arrogance!’

Hella murmured, `Haven’t human rulers always done this?’

Hex said, `I’m hoping we can use its arrogance against it.’ She inched forward cautiously. Still they weren’t challenged. The hull of the bastion was a smoothly curving blankness before her, reflecting not a photon of starlight. She sensed the Black Ghost in there somewhere, watching, drawing out the moment as she was. `Come on, you bastard,’ she muttered. `You know I’m out here. Let’s see what you got.’

The black wall quivered. Then it split along a seam, revealing a pale silvery glow. When the wound stopped dilating it was a vertical slit hundreds of metres long, more than wide enough for the palette to pass.

`I can’t see inside,’ Jul said.

`Our suit sensors don’t work,’ Hella said, sounding alarmed.

`But the invitation’s clear,’ Hex said tightly. She brushed her hands forward.

The walls of the bastion slid past her; the fortress’s hull looked no more than paper-thin. Twenty metres inside the hull she brought the palette to a stop. Her visor showed her nothing but empty space, a sphere kilometres wide filled with a cold silver-grey glow.

Then the ur-Ghost hide around her began to crumple and blister, and a harsher light broke through, shining directly on her. She threw up her hands to protect her vision. She heard the others cry out. The hide, scorched, crumbled and fell away.

Cautiously she lowered her arms. Now she could see what the sensors hadn’t been allowed to show her. This space wasn’t empty at all. It was filled with Silver Ghosts, spheres like droplets of molten metal, and ur-Ghosts of every shape and size, faceted and spiny, ranked around her in a hexagonal array that filled space as far as she could see. They were motionless, positioned with utter accuracy, objects of geometry rather than life. And, scattered through the ranks of silent Ghosts, lanterns pulsed, blue-white: models of the pulsar that was destroying the world, they were marks of adherence to the Ghosts’ Destroyer god.

This was nothing like the way humans had seen Ghosts behave before, over centuries of contact and warfare. The command of the Black Ghost, here at the heart of its empire, was total.

Hex’s palette-ship hung like a bit of flotsam before this symmetrical horde. With their skin covers burned away, her crew sat cross-legged in their little hollows, cowering. `Everybody OK?’

`What do you think?’ Jul said.

Borno was staring at the arrayed Ghosts greedily. `Lethe,’ he said. `There must be thousands of them.’

`Actually more than a million.’ The voice, delivered through their translator boxes, was flat, impersonal, artificial.

Hex looked into the geometric centre of the sphere, for she knew that was where it would be; its sense of its own importance would admit nothing less. And there she saw a black fist, a sphere twice, three times the size of those clustered around it. The ranks of Ghosts parted in shining curtains, and that central dark mass slid forward.

Hex heard the harsh breathing of her crew. `Take it easy,’ she murmured. `We’ve come this far-‘

`I’ve let you come this far,’ said the Black Ghost. `Did you think your absurd concealment would fool me?’

`Actually no,’ Hex said. `I thought you would be so arrogant you would let us in anyhow. You’re very predictable.’

The Black Ghost rolled before them, its coating black as the inside of her own skull. Hex was guessing at the psychology of an alien being exceptional even among its own kind. Well, the Black Ghost showed some characteristics of humanity, and no human, especially the arrogant sort, liked to be mocked.

Almost experimentally, Hex raised her arm and held it out straight, pointing at the Black Ghost. An energy weapon was built into the sleeve of her suit. She fired; her suit reported the energy drain. But there was no sign of the discharge.

Her crew quickly tried the other weapons at their disposal. Nothing worked. With an angry cry Borno even hurled his knife. It crumbled to dust before it left his hand.

The Black Ghost said, `And you call me predictable?’

`We’re here to kill you, you bag of shit,’ Borno said.

`To kill me, yes. Humans walk in death. Each Ghost is a complete ecological unit. When we went into space we brought the life of our world with us. Whereas you killed off your ecology, killed the world that produced you, all of it except yourselves, and the pests and parasites too wily to be eradicated. You even call us Ghosts, named after imaginary creatures you associate with death. How appropriate.’

`And what about you?’ Hella asked. `How many humans have you slaughtered - how many of your own kind have you put to the flame?’

`Ah, but I am different. I relish death, as you do. Can you see my black hull? These others are silvered to save their heat. I relish the obscenity of waste - as you do. I am like you. Or I am like our Destroyer god of old.’

`Your own kind despise you,’ Borno said.

`That may be. That is why I brought back these others …’ Hex’s translator box interpolated, the ur-Ghosts. `These, forged in the cold desperation of our race’s most difficult age, don’t deny what they are. It is strange. Once the ur-Ghosts were called back from space, to help save a dying world. Now I have called them again, back from the deeper darkness of the past, to help me save my kind from humans.’

`It’s crazy,’ Hella whispered.

`So you have us,’ Hex said. `What now?’

`You will serve me. Three of you will be given to my ur-Ghosts, my scientists. We will drain you of what you know, and then use you to explore ways of killing humans. Oh, you will be bred first; we are running short of laboratory animals. The fourth will be flayed, kept alive, and sent back where you came from. Perhaps you, the commander. A warning, you see; a statement of intent. Don’t you think I know human psychology well?’

`Not well enough,’ Borno said.

Hex snapped, `Gunner-‘

`For the Engineers!’

With a roar Borno straightened his legs and hurled himself out of his palette station, straight at the Ghost’s bland black hide. In mid-flight his suit slit open and fell away, leaving him naked save for underwear, his head, hands and feet bare. His last breath frosted in the vacuum, his mouth gaping. But he held out his hands like claws.

Jul screamed, `What’s he doing? He’s killing himself!’

Hex, stunned, could only watch.

Borno landed on the Ghost’s night-dark hide and grabbed big handfuls, pulling and crumpling. The Black Ghost rolled, trying to shake off its assailant. Around it the other Ghosts bobbed, agitated, but they had no way to help; they couldn’t fire on Borno for fear of hitting the Black Ghost itself.

Then Borno took a mouthful of hide, bit down hard, and arched his back. The Ghost’s hide ripped, and a clear fluid laced with crimson boiled within the wound. Borno’s eyes were bleeding now, his ears too, but he dug into the Black Ghost with his teeth and nails, the only weapons he had left.

`We have to help him,’ Hella called. She breathed hard; Hex sensed her psyching herself up to follow Borno. `Are you with me?’

`All right,’ Hex said. `On my mark-‘

Before they could move one of the Ghosts broke ranks. A perfect silver sphere, it swept down purposefully on the Black Ghost and its clinging human assailant. A slit opened in its own belly, a weapon nozzle protruded - and a projectile fired neatly into the black hide through the wound Borno had opened. The Black Ghost emitted no sound, but it quivered and thrashed. Borno clung on, but he was limp now.

And every other Ghost among the million arrayed around them froze in place.

As the Black Ghost suffered its death throes, the assassin came drifting to Borno’s vacated station.

Hex asked, `Integumentary?’

Hella said, `How do you keep doing this?’

`I suggest you get us out of here, pilot,’ said the Ghost. `Without leadership the troops are paralysed, but they will react soon. If you want to live-‘

`Not without Borno,’ Jul said.

`He’s already dead,’ said the Ghost.

`No!’

The Integumentary spun in its station and spat another bullet, this time neatly lancing through Borno’s limp body. `Now can we go?’

Hex grimly drew her hands towards her lap. The palette shot backwards out of the bastion, and into open space.

VII

The palette hovered at the rim of the system. The misty, dying star of the Ghosts was still visible, as was its intensely blue companion.

`They won’t find you here,’ the Integumentary said, still nestling in Borno’s vacated pod.

Commodore Teel’s disembodied head appeared before Hex. `So the Black Ghost is dead. Good. Now we will see how the war turns out. You did well, Hex.’

`Borno did well.’

`He will be remembered.’

The Integumentary seemed to feel its plan had worked out as it hoped. It had been able to penetrate the Black Ghost’s bastion, even smuggle in a weapon so crude it wasn’t picked up by the defensive systems. But it could never have penetrated the Black Ghost’s hide if not for Borno’s attack, which the Black Ghost clearly hadn’t anticipated.

Teel said, `So the most powerful Ghost in generations was defeated by human qualities: Borno’s raw anger and courage, and the Black Ghost’s own arrogance.’

The Integumentary murmured, `And what could be more human than savagery and arrogance?’

Hex was still trying to understand what had happened. `Ghost, when your sun died, there was a bloody battle for survival. You’ve spent a million years denying that about yourselves. But the Black Ghost saw it was precisely that streak of primitive brutality you had to rediscover to fight humanity. It might even have succeeded. But you couldn’t bear the image of yourself it showed you, could you?’

The Integumentary said, `The Black Ghost was an anomaly. This is not what we are, what we aspire to be.’

Teel looked at Hex. `Pilot, it isn’t just their past that the Ghosts want to expunge, but what they have glimpsed of their future - or anyhow that’s what the analysts in the Commission for Historical Truth have made of this incident.’

It was a question of natural selection. For centuries, Ghosts had been losing battles to humanity. Only those capable of dealing with humans - of anticipating human intentions, of thinking like a human - survived to breed. `It’s a selection pressure,’ Teel said. `Only those Ghosts who are most like us have been surviving. So maybe it’s not surprising that there should emerge a Black Ghost, a Ghost so like a human it organises its own hierarchical society, fights a war like a human commander. What do you think about that, Ghost?’

The Integumentary rose up out of the palette cradle. `I am relieved our business together is done. The Black Ghost is dead. The exploitation of interdimensional energy will be closed down, the research destroyed. It is a weapon too dangerous to be used.’

`Until we rediscover it,’ Hella murmured.

Teel wasn’t done yet. `You can’t stand this, can you, Ghost? You needed humanity to resolve this problem among yourselves. And to do it, you had to think like a human yourself, didn’t you?’

The Integumentary said, `It is true that we would rather go to extinction than to become like you. Is that something you take pride in? Pilot, the ancient star system will be restored to its proper time. You have only seconds before the energy pulse that will follow. I tell you this as a courtesy. We will not speak again.’ And it disappeared, as if folding out of existence.

Jul said, `Seconds?’

Hella said, `How fast can this thing go, pilot?’

`Let’s find out,’ Hex said, and she flexed her gloved hands. `Everybody locked in? Three, two, one-‘

The Black Ghost inspired its kind’s last effective stand. After its fall, the Ghosts’ political unity fragmented, and they fell back everywhere.

For the Ghosts, the consequence of defeat was dire.

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