Raft a short story by Stephen Baxter

Foreword

The short story 'Raft' came from a throwaway piece of speculation I read on the fine-tuning of physical parameters in our universe. If gravity were a little stronger, stars would be smaller and would burn out more quickly ...

'Raft', of course, turned out to be an important story for me. It was always too big an idea to cram into a short story; I had to wrestle it down from 10,000 word early drafts. And even after it was published, in Interzone, my mind wouldn't let go of the scenario, coming up with fresh wrinkles on the central conceit. When I started to think about a first novel, the universe of 'Raft' was an obvious place to return to, and the story is now a very rough sketch of what the novel became.

Raft

Rees and Glover padded towards the cable.

Plant-like, the cable thrust upwards out of the deck's plates, creaking under the weight of the Raft and all its occupants. A hundred metres up it was tethered to the hub of a tree. The great wooden wheel rotated complacently; Rees was close enough to feel the downwash from its aerodynamically shaped branches.

Around the cable two skitters were dancing out their courtship. The little round creatures fizzed as they flew.

Now the boys were only metres away - and Glover giggled, his wide face flushed with excitement. Rees glared; but the skitters continued their dance, their dim intelligence unable to distinguish the boys' motion from the shadows cast by the falling stars.

Rees grinned and motioned Glover forward. He spread his hands wide. Everything seemed to become vivid: he could count the rivets under his bare feet; he could make out the male shape of the nearest skitter's rotor blades ...

Now the male sensed the presence of Rees' gravity well. It darted in alarm. For a few seconds Rees allowed the creature's gravity pull to work over his palms; it was like the touch of a child. Then, with a stab of regret, he closed his hands and crushed the skitter's substance -

- and the breath was knocked out of him by Glover's bulk thumping into his back.

"You bloody idiot, Glover."

Glover grinned triumphantly: "I got it!" The female's spokes protruded from his fist.

Obscurely disgusted, Rees pushed himself away from Glover's gravitational cling. "Yeah, well, we've only got a few minutes left before Hollerbach comes down this way. Come on - up into the tree -"

Clutching his skitter, Rees led the way up the cable, clambering with hands and feet. After the first dozen metres they'd climbed out of the diffuse gravitational field of the Raft; now their climb was opposed only by the pull of the Core, far below.

Rees reached the tree's hub and made his way along a rotating branch. Air washed over him; he took care to avoid splinters from the branch's leading edge. On reaching the stationary rim he hid himself in the foliage. There was a smell of green, growing things.

Breathing hard, he surveyed his world.

The Raft was an enormous dish that brimmed with life. It was nearly the end of a work shift, and people slid along the avenues to their homes, skirting each others' irritating gravity pull. Many of them, Rees knew, would be carrying rations from the supply machines that hulked around the rim of the Raft. Others carried tools after a shift spent maintaining the huge old supply devices.

Now a wave of children came rustling to greet the homecoming workers. A party of Officers passed below Rees, their shoulder ribbons sparkling in the shifting starlight.

Rees stood up now, balancing on the tree rim. With his head thrust out of the foliage he could see how the Raft was suspended from a thousand cable-tethered trees. The flying forest was a mass of stately rotation, and it was adorned by a cloud of skitters that caught and softened the starlight.

He craned his neck upwards, eyes raking the sky.

The ruddy air was filled with falling stars, an endless rain of them tumbling down to the Core. Here and there he saw the tiny flashes that marked the end of the stars' year-long lives. Far above him was the Vanishing Point: the place the stars fell from. As he stared into the Point he felt as if he were slowly rising; the stars spread out from the Point as if the Raft were climbing a star-walled shaft.

And today there was a new spark right at the Point. A young star, he wondered, poised to fall directly on them?

Relaxing his neck, he let his gaze roam once more over the Raft's scarred bulk. Hidden somewhere beneath, of course, was the mysterious red glow of the Core itself. But the only way to see the Core was through one of the Observation Ports set in the floor of the Raft ...

And that reminded him what he was doing here.

He clutched tighter on his skitter. Whenever he'd gone near a Port recently there had been a Scientist waiting to chase him away. Scientists! Fat-bellied fools who acted to a man as if they owned the place ... and without a doubt the worst of them all, the one who seemed to take the greatest pleasure in harassing Rees and his friends, was Hollerbach.

Rees smiled tightly. Well, today old Hollerbach would get what was coming to him -

Right on cue, Hollerbach approached grandly from the rim, the spectacles he affected perched on the end of his nose.

There was a snort from Glover's hideaway. The old Scientist stopped suddenly, his head cocked to one side. Rees felt his pulse quicken. If that fool Glover had messed this up -

But the Scientist seemed to relax. He continued on his way, a slight smile on his lips.

Rees breathed again. He fingered the skitter. He wanted to do this right. He swayed a little, letting the gravitational fields of the Core, the Raft, the tree, play over him like breezes ...

Then he launched the skitter into the air. The makeshift missile orbited around the Raft's mass centre and curved downwards -

There was a soft thud. Hollerbach was glaring up, hands on hips, a skitter on the deck beside him. Glover's face popped out of the foliage. "I nearly got him, didn't I?"

"But -" Rees found himself growling with rage. Glover had dropped his skitter straight down. Where was the skill in that? With dismay he watched his own projectile loop to the deck. If not for Glover he would have got Hollerbach right on the bald spot.

"And what do you think you're doing? Officers! Officers!"

Automatically the boys climbed along their branches and slid to the ground. Rees wondered whether apologising would get him out of this - Hollerbach was only a Scientist, after all ...

The party of three Officers who had passed earlier came running. "Mr Hollerbach. I hope you're not hurt -"

Rees recognised the voice and felt sickened. Could they be so unlucky? But it was indeed Captain Smith himself; Rees saw huge arms folded across an officer's belt, and he felt the tug of a belly covered by a ragged shirt. "I know this one. You're Bob Rees' boy. Michael, isn't it?"

Rees nodded, filled with shame.

"Bob's one of my best men. And you've let him down. What were you thinking of? Don't you realise you could have killed Mr Hollerbach, here?"

"What, with a squashed skitter?" Glover sneered. The Captain scuffed his head; Glover started to cry.

"How old are you two?"

"Twelve," Rees said.

"Twelve, and you don't know yet how important the Scientists are? Without the Scientists we'd all have died off generations ago. It's the Scientists who guide us when we have to move the Raft to avoid falling stars. Did you know that? No?

"Well, this is obviously a serious matter. Do you propose a punishment, Mr Hollerbach?"

Glover stopped crying. His eyes narrowed. "He made me do it," he said rapidly.

Rees bit his lip.

Hollerbach eyed Glover. "I've no wish to punish the innocent, he said in his thin voice. "Let him go." Glover scampered away.

The Captain scratched his tangle of beard. "You don't believe that, do you?"

Hollerbach didn't answer. "And as for this ignorant scoundrel - I propose to take him on as an apprentice at the Laboratories and teach him a few lessons."

Rees gasped.

The Captain said, "I know you're short of apprentices, and I suppose it's just ... but for how long?"

Hollerbach smiled, his eyes invisible behind his spectacles. "Shall we say - six years?"

"You can't do that!" Rees felt tears prickle his eyes.

The Captain drew Hollerbach aside. "Look, Hollerbach, don't you think that's a little heavy? Give the boy a few chores and let it go."

"Let it go?" Hollerbach arched back his head, pale eyes blazing.

Even the Captain, Rees realised, couldn't save him. "Very well. I'll inform Bob, have the lad's things sent over -"

And Rees found himself trailing after Hollerbach, his world in pieces.

He was allowed to see his mother once. After that he set his face into a mask and kept it that way, rejecting all Hollerbach's mocking attempts to make conversation.

The Laboratories were a jumble of oversize huts at the centre of the Raft - wooden, of course, like the rest of the Raft's buildings. Rees was set to work at simple chores - cleaning, cooking, laundry - and his misery deepened at the squalor of the place. The Scientists were mostly middle-aged, overweight and irritable. Brandishing the bits of string that denoted their ranking, they moved about their strange tasks and ignored him.

The shifts passed slowly, but gradually Rees' interest was drawn by the contents of the rooms he dusted. There were glass jars with tree sap in various stages of hardening, great ledgers showing the estimated paths of the stars falling around the Raft, painfully computed schedules for moving the Raft itself.

He found a brilliant sphere the size of his thumb; around it on silver wires orbited nine orbs. A plaque on the base said "Solar System". Rees spent hours watching the painted planets ...

And there was a Library.

For days Rees dusted the surfaces of the great books, averting his eyes from the spines. "Ship's Log ..." "Technical Report ..."

Finally he pulled down a volume and opened it carefully. The paper was yellow with age; clouds of dust billowed up from each page.

"So it can read, can it?" Hollerbach grinned, showing chipped teeth.

Rees thumped the book shut. "Of course I can read," he snapped. "And what I've read is all wrong."

"Oh, yes?" Hollerbach's eyes sparkled behind his spectacles. "And it can talk, too!"

Rees went on stubbornly: "Yes, it's wrong. According to this, when the first Crew flew here in their ship -"

"You know the story, surely." Hollerbach took off his spectacles and began to polish them on a corner of his shirt. Rees tried to interrupt, but Hollerbach had settled into his stride. "Five hundred years ago a great warship - chasing some forgotten opponent - blundered through a portal. A gateway. It left its own universe and arrived here.

"The ship instantly imploded in its own gravity field ... but the Crew survived. Out of the debris they constructed the Raft, twelve kilometres wide; they trapped the trees that support us; they salvaged books and supply machines - and they set up the fragile social order that has kept us alive to this day."

"Yes," said Rees, "but it says here they found the sky blue, and all the stars yellow or white. But now the stars are mostly red - even the young ones - and so's the sky."

"Very observant. But the arrival was generations ago. The nebula - the cloud of gas all around us - has changed." Hollerbach replaced his glasses and scratched the back of one age-spotted hand. "Do you know what I'm talking about, boy? There are many nebulae here, around other Cores ... the nearest is above our heads, beyond the Vanishing Point.

"The stars in the nebulae shine by burning hydrogen. When they die, after a year or so, they leave more complex substances behind. The stars keep us alive. They give us light and warmth; they provide the complex molecules from which the native life - trees, skitters - is constructed, and which are the raw materials for our supply machines.

"But our nebula is running out of hydrogen. Another few years and no more stars."

Rees frowned. "What about us?"

Hollerbach shrugged cheerfully. "Well, the trees will die. And we'll fall. And that will be that." He eyed the boy. "Unless some bright spark works out what to do about it."

Carefully, Rees asked: "What's hydro-gen?"

Hollerbach laughed and clapped Rees' back. "You've got a lot to learn, little expert, haven't you?" He studied Rees and seemed to come to a decision. "Follow me," he barked.

He took Rees to an Observation Port at the centre of the Lab complex. Rees stared. Most of the Ports he'd seen outside were simple windows set in the deck - but this was a pool of light metres wide; it was encrusted with instruments that peered into it like curious insects.

Hollerbach, grunting, lifted Rees up so he could see into a telescopic monitor. As the magnification increased Rees felt he was plummeting into the Core itself.

"Gravity is the great secret of this absurd place," Hollerbach said. "The force of gravity is a billion times stronger here than in the universe we came from. Do you know what that means? Even an object as puny as a man has a significant gravity field. I can feel your weighty presence even now, young Rees.

"And the celestial mechanics are a joke. If the solar system were moved here, the sun's increased pull would whip Earth round its orbit in seventeen minutes. Seventeen!

"The Core is the heart of this nebula. It's a black hole with the mass of a galactic nucleus - ten thousand suns - but in this fairy-tale place it isn't much larger than the solar system.

"The Core's gravity field is what holds the nebula together. The whole thing, stars and all, is falling gradually into the black hole. But life forms prosper, precariously, by being light enough to fly out of the hole's grip. And we have survived by harnessing the flying trees ..."

Rees, understanding about one word in ten, just looked. The Core was a blood-red sphere wreathed in mist. The light came from nebula material falling into the Core, Hollerbach explained; the Core's gravitational fist crushed it until it shone.

The voice of a crier came to them, calling out the shift change.

Hollerbach lowered Rees to the deck. "Now, listen to me. Take a few hours a day off your chores and we'll see what you can learn. Chemistry, maths, physics, the history of Earth - it might be entertaining ..."

Rees hurried away, his head full of glowing mysteries.

As he studied, Rees' resentment faded to a dull ache. There was too much to learn. The Scientists were undoubtedly a bunch of elitist old buffoons, largely deserving the contempt of the rest of the population - but they'd kept knowledge alive.

And without knowledge, Rees soon realised, they would soon die here.

One shift he found himself queuing for food before the ragged bulk of a supply machine. Absently he stared at the scorch marks which showed where the device had been burnt from the guts of the warship. Weary people muttered; the star falling from the Vanishing Point had become a beacon that blazed down on them, banishing the nebula's pastel shades.

A short man with a wiry beard turned to Rees and said: "Why the hell don't the Scientists move us out from under that thing? And why doesn't the Captain get off his fat backside and do something about it, I'd like to know -"

Rees collected his ration and hastened away. But he thought of the last time he'd seen Captain Smith - a deflated figure with helpless eyes watching the discomfort of his crew ...

He hurried back towards the Labs. Deserted streets were punctuated by knots of young men - some in Officer's colours - who argued and waved fists.

"Hey, Rees. Rees!" Glancing about shiftily, a squat young man sidled out of a building.

Warily Rees stopped and put down his containers; the gravitation of the sloshing water tweaked at his legs. "What do you want, Glover?"

"Well, well." Glover laughed, scratching at the stubble on one cheek. "Four years gone, eh? Four years of washing and carrying for the old farts in the Labs. And two more to go. At the age of eighteen you'll still be skivvying -"

Glover's shabby jacket was decorated with a junior Officer's ribbons. Rees felt acutely aware of his own lack of colours. "It's not like that. There's more to them than we realised, as kids -"

Glover sneered. "Yeah?"

"People despise the Scientists. Something's gone wrong, somehow. They even have to trick people to become apprentices -"

"Like you."

"Like me, yes." Rees could smell the sourness of Glover's breath. Disturbed, he tried to tell Glover some of what he'd learned: of another universe where the stars were a million miles across, not five or ten; of constellations that lasted - not months - but billions of years.

But none of it seemed real. He struggled for words.

"Crap." Glover breathed hard through flaring nostrils. "Forget the fairy stories, Rees. Most people on this Raft aren't too fond of the Scientists. Why are the trees dying? Why are the food machines failing? Even the air's foul half the time. And why don't they move us out from under that damn star up there?"

Rees felt tremors of unease. "What are you saying?"

Glover's eyes narrowed and he moved so close that Rees felt the pull of his squat bulk. "Do you know what this is?" He took a bottle from his jacket and handed it to Rees. Rees removed a plug of cloth from the neck and smelled the contents: alcohol. "Light it," said Glover, "and throw it. Somewhere that will burn; say one of those big Libraries they have. You'll be able to do it. They trust you."

The bottle felt as if it were already burning Rees' hands. "Do you know what you're suggesting? This is a bit bigger than lobbing skitters at an old man -"

"Listen, Rees. There's coming a time when if you're not for us you're against us." Glover took back the bottle and walked away.

Rees picked up his burden. He wasn't afraid of Glover, he reflected - but maybe those ranked with him were something to be wary of ...

He made his way thoughtfully back to the Lab compound.

When the end came, it came fast.

Rees was nineteen. He still spent most of his time with the Scientists - but now by choice. He stood with Hollerbach at the Labs' Observation Port. In the false colours of one monitor the Core was a blue-green that brought a catch to Rees' throat. "It looks like a world," he said.

Hollerbach nodded. "Like a portrait of Earth, yes? But in many ways it is a world ...

"We've found there's a sort of gravitic chemistry going on down there. In our home universe gravity is weaker over short ranges than other forces, which is why our bodies are cages of electromagnetism. Around that Core, though, we've detected massive molecular structures bound by gravity ... It's a different order of creation -"

There was a smash of glass, a puff of flame that knocked Rees onto his face.

He staggered to his feet, coughing. The walls of the hut were scorched and bent outwards; books burned like candles. Beneath his feet there was half a broken bottle. He picked it up. It stank of alcohol.

Hollerbach sat on the rough floor, his cheeks smudged with soot and tears. He held up broken spectacles. "Damn," he said, as if puzzled. "Five hundred years old, they were. Of course they didn't work ..."

Ignoring Hollerbach's coughed protests, Rees got an arm around the Scientist's chest and hauled him out of the fire.

Scientists came waddling out of the burning buildings. They were clearly terrified, but they were laden with books and instruments. Silhouetted against the fire were the running forms of angry men.

At a safe distance, Rees gently lowered Hollerbach. He counted five blackened bodies on the deck.

As the blaze died the attackers gathered in a tree's rotating shade. They were a dozen or so young men, and they panted with exhilaration. Rees approached them. "At least," he said quietly, "you had the decency not to slaughter any more of those old men."

A broad, soot-smeared face challenged him. "You keep out of it, Scientist," Glover sneered. "Your time is gone."

Rees' rage trembled in him. "And half of you killers are still wearing Officers' lights -"

"There's no more Officers," Glover grinned. Sweat gleamed on his lip. "Captain Smith is dead. We're in charge now. And things are going to change -"

Rees felt his stomach tighten, as if some dark object were passing below the deck. So it had happened - and so suddenly. The order that had sustained them was gone, to be replaced by - what?

He looked to Hollerbach. The old Scientist's eyes rested on him expectantly.

Suddenly Rees felt an almost intolerable power. He was at the Core of this coup; his actions now could kill or save them all ...

But that seemed absurd. What did Hollerbach expect of him? What could he do?

The moment stretched. Then, deliberately, Rees spat into Glover's face. "Murderer," he said.

Glover's eyes narrowed. He stepped towards Rees, muscles bunching across his chest.

"Watch it, Glover," someone called. "He's got a weapon."

Rees held up the half bottle. "What, this? All right, Glover - hand to hand. Just you and me." He hurled the glass as hard as he could, not quite vertically. It sparkled as it shot through the branches of the tree above them.

Glover crouched, spread his fingers wide and bared his teeth.

Rees kept talking. Just a few seconds - "And what's the next target, Glover? The food machines? -"

The half bottle orbited perfectly around the tree's mass centre and slammed into Glover's back. He went down howling, hands clawing at his spine.

For long seconds nobody moved, forming a tableau around the writhing man.

Then Rees knelt, forced his hand into the wound and dug out the glass. Glover passed out.

Rees stared at his hands. He'd never dreamed there would be so much blood ...

Glover's shocked followers were beginning to stir. Rees forced himself to speak. "I know what you're thinking," he told them. "I cheated, I didn't play by the rules. Right?

"Well, what do you think this is?" he screamed suddenly. "A game for children? I wasn't going to let this cretin walk away from here to kill us all.

"And if you want rules, I'll give them to you. You're going to make amends for what you've done. You're all that's left of the Officers on this Raft. People rely on you to keep order and help them survive - and you're going to follow me right now and do just that."

Giving them no chance to reply he turned on his heel and walked away. After a few seconds he heard them begin to follow.

He walked past Hollerbach. He wasn't sure what he wanted from his old tutor. He'd been set a problem and he'd solved it, hadn't he? Didn't he deserve some recognition, some praise?

But Hollerbach just stared at Rees' bloody hands and shuddered.

Rees lay on a pallet and stared up through the Lab hut's ruined roof. When he closed his eyes he saw himself once more marching his band of Officers around the rim of the Raft, securing the supply machines with his voice and his fists - "Hollerbach, I haven't got a lot of energy left," he said wearily. "So get to the point."

Hollerbach sat stiffly on the floor and spread his hands. "Rees, you're becoming brutal," he said. "But you ... contained the situation today. And I think you deserve to know what's really happening here."

Rees bunched his fists. "Right. You know what brought us to this insurrection - your failure to shift the Raft out from under the falling star."

Hollerbach peered over his missing spectacles. "Don't bluster, boy," he boomed. "You know that we face a far more serious danger even than a falling star."

"The exhaustion of the nebula," said Rees. "So?"

"So we have a plan." Hollerbach smiled, his cheeks crackling like old paper. "A plan to use the star to get us out of this cloud of death."

Despite his aches, Rees sat up. "How?"

"We stay close to the star. It pulls us through a half- orbit as it passes and hurls us deeper into the nebula."

Rees frowned. "Would the Raft survive the tidal stress?" Then he thought it through further. "And even if we made it, we'd be heading the wrong way. The nearest other nebula is above our heads ..." His eyes widened. "You're not planning to orbit this Raft round the Core?"

Hollerbach laughed, seeming exhilarated. "Outrageous, isn't it? We'll bounce off the Core's gravity well like a rubber ball, soar back up and out of this nebula to our new home."

Rees shook his head. "You're crazy. You'll kill us all."

Hollerbach frowned. "Well, the choice is to become the prize in a race between famine, suffocation and cold ..."

"Why is all this a secret?"

"Rees, most people on this Raft can't think beyond their next trip to the food machines. Do you imagine they'd happily agree to a madcap scheme like this?

"We had Captain Smith's support. But Smith is dead, and we Scientists are a bunch of despised fools to be killed and maimed ... Frankly, Rees, what worries me more than anything else is that we have nobody left alive who could persuade the people to cooperate." His rheumy eyes were fixed on Rees.

Rees lay back, feeling the weight of the Raft settle once more over his shoulders.

Rees clung to the tree rim, his world spread out like an animated map. "Come on, you!" he heard Glover bellow from the deck. "Yes, you! Use that bloody knife!"

A man installed in a tree a hundred metres from Rees looked round and scrambled around his rim to a fresh-looking patch of wood. With a crude metal dagger he stabbed, again and again. The tree tipped its rotors, trying to escape from this brutalization of its flesh, and altered its course with a great wooden groan.

"Better!" shouted Glover - and Rees noted a dozen men in neighbouring trees redoubling their efforts, just in case Glover had meant them. Gratified, Rees watched Glover's squat form prowl among the cables. With a simple acceptance of Rees' greater authority Glover had become one of Rees' most trusted deputies.

Now every able-bodied man and woman on the Raft was up a tree, and with cries and kicks and stabs they were goading the great leafy cloud into motion. Cables sang and children cried as the deck juddered sideways.

Rees crawled around his rim in an effort to find healthy wood. In the nebula's fading starlight he could see how the tree's foliage had grown limp. If it hadn't been for the young star poised like a fist above them, the trees might have gone already - maybe the Scientists had been wiser than they knew.

It took days more struggle before Rees felt satisfied; but at last he allowed the weary people to trickle down their cables like sweat drops.

Then, all too suddenly, it was time.

The falling star slid away from the zenith. Hollerbach stared up at it; for safety's sake he had been strapped to a pallet under the open sky. "Well, it's going to miss us," he fretted, "but did we move the Raft far enough?"

Rees said nothing. He'd anchored himself with both legs to a cable, and he laid one arm over the old man's shoulders.

The star flew suddenly down the dome of the sky; shadows slid over buckled plates. The shifts of the star's gravity field pulled like claws at Rees' stomach. Soon, now -

A jolt, like a drop through a few metres. Then the Raft started to tilt.

The structure swung neatly around the star, tipping so that it kept the upper face to the star. People cried out and deck plates groaned. Rees watched two trees smashing together; huge splinters rained down over the deck.

For a moment he was upside down, the distant stars rushing upwards, and there was the Core itself poised above him, cool and red and enormous. But centripetal force and the Raft's gravity field kept him glued to the deck, and then the Raft whipped through the rest of its rotation and righted again, dangling from its trees like a toy.

Rees helped Hollerbach up. The old man groaned theatrically and clung to the swaying cable.

Rees felt oddly light, his step springy. They must be in near free-fall, he realised; only the Raft's own gravity well was holding him to the deck. He watched the star shrink to a point far above him. The more distant stars were cold and red ... and they were floating upwards.

"Look at that," he breathed. "We're overtaking the stars. It's worked ..."

Its remaining trees bumping after it, the Raft hurtled into the gravity well of the black hole. The time of greatest danger - closest approach to the Core - was to last a few days.

Over the Labs' Observation Port they lashed together a crude radiation shelter from deck plates. The Scientists worked their instruments, muttering to themselves and making obscure notes.

During closest approach Rees spent hours with Hollerbach at the optical monitor, peering at the Core. The Raft seemed to be gliding over an ocean of smouldering smoke ...

Hollerbach's call woke him from a sleep disturbed by the groaning of metal. Hollerbach pointed at the monitor. "Look in there ..." He bared brown teeth.

In the sea of smoke there were circular shadows, each big enough to cover a thousand Rafts.

"Life," Hollerbach said. "Based on gravitic chemistry. Those creatures must feed off the infalling nebula matter. Of course, that will dry up. But then they'll have the trickle of energy evaporating from the black hole itself.

"These animals are the true inhabitants of this place, you know, Rees. We're transient interlopers ..."

The Raft lurched downwards. Hollerbach fell backwards with a grunt of pain; the Scientists milled about in confusion.

Rees struggled to keep his feet. The monitor showed one of the plate creatures looming out of the ocean beneath them. A jet black surface thrashed; it was as if a fist was pushing through a sheet of rubber and reaching out at them -

"It must be sensing the power sources in our food machines," Hollerbach shouted. "Its gravity field will rip us apart." He closed his eyes and clung to the floor.

"Like hell," muttered Rees, and he pushed his way out of the shelter. With no clear idea in his mind he began to make his way towards the rim.

Half a kilometre out he met Glover staggering the other way, a bloodied nose masking his grin. "I was coming to find you," he said thickly. "What are we going to do about this, then?"

Rees squeezed his shoulder and motioned him to follow.

It took them painful hours to cover the six kilometres to the rim. Again and again the deck tilted and bucked, slamming into their feet. From collapsed radiation shelters they heard cries of pain. They ignored them all.

At the rim they slumped to the deck and lay still, panting. Rees risked a glimpse over his shoulder. Since they were being attracted back to the Raft's centre of gravity the deck felt as if it were tilted at about twenty degrees; vertigo swept through him and he dug his fingers under a loose plate.

Then he looked up.

A pseudopod towered over the rim like a vast arm, muscles flickering.

"That'll crush us in a second," Rees whispered. He got to his feet and stumbled to the nearest food machine. "We need levers. Where's the machine's toolkit?"

Panting, constantly losing their footing on the deck's shuddering, they levered at the machine. Rivets snapped with metallic rings.

The pseudopod loomed closer; Rees' stomach felt the quiverings of its gravity field.

Finally the machine was slapping thunderously at the deck, attached only by a few rivets at the outer edge. The two men spent minutes straining to reach. At last Rees stood back, breathing hard. "It's no good," he said.

Glover was silent.

Rees felt a prickle of unease. Glover was a few metres back from the rim, standing on the balls of his feet. His eyes were narrowed. It was a look that made Rees think of a treacherous little boy, a murderous young man.

He hadn't expected this. Had Glover been faking loyalty, waiting for a chance for revenge?

Glover said softly, "Remember how we dropped those skitters on old Hollerbach? And you told me off for dropping mine straight down? Well, you won't mind if I don't attempt a fancy orbit now - if I just give you a straight drop?"

He began to stride towards Rees, muscles working in his shoulders. Then he began to run, and he yelled, pushing the noise before him.

Rees prepared to resist ... then felt something give. Let Glover have his moment of revenge. If he'd failed to save the Raft he didn't want to stick around to see the final disintegration ... He closed his eyes.

There was a bone-breaking crunch, a scream of pain and determination. Rees opened his eyes, shocked to find himself unhurt. Glover was spreadeagled against the side of the machine, blood seeping from his face.

The supply machine rocked back on its hinge - and then, with a final popping of rivets, it tipped over the rim and tumbled downwards. The pseudopod grabbed the morsel and receded.

Glover was gone.

The deck's tremors faded. Wearily Rees turned and made his way back to the Labs.

With the Core receding beneath them, the survivors crawled from their shelters. The few remaining trees creaked over their heads.

Rees limped around the Raft with Hollerbach, watching the bodies of the dead being dumped over the rim. There was no shortage of sick and dying ... and the suffering of those who had insisted on staying out under the Core's hard rain would be with them for many days yet.

About a third of the Raft's population had not survived. They saw hardly any children or old people.

"But I'm still here," Hollerbach pointed out.

Rees managed to laugh. "You always were a persistent old sod."

Hollerbach slowed, wheezing; Rees helped him lower himself to the deck's scuffed plates. "Listen," Hollerbach said breathlessly. "You mustn't feel badly. Without you we'd all be dead, not just the weakest."

Rees stood straight. "You know, I've been thinking," he said. "Maybe it's time we did more than just endure. You once told me that one of the by-products of stellar fusion is iron." He glared at the sky. "There must be mountains of the stuff floating about in that new nebula. I say we harness a few trees and go looking. We've retained enough understanding to get a technology going. We could build machines of our own, ships even. Perhaps one day we might even find our way back to our home universe ... What do you say, Hollerbach? Hollerbach?"

The old Scientist's eyes had closed. He slumped forwards and then sideways, subsiding gently to the deck plates as gravity won its final battle.

Rees carried the body to the rim. He watched until it was lost amid the falling stars.

Then he turned away, and went to work.

(c) Stephen Baxter 1989, 1997