MOON DUEL

FRITZ LEIBER

FIRST HINT I had we’d been spotted by a crusoe was a little tick coming to my moonsuit from the miniradar Pete and I were gaily heaving into position near the east end of Gioja crater to scan for wrecks, trash, and nodules of raw metal.

Then came a whish which cut off the instant Pete’s hand lost contact with the squat instrument. His gauntlet, silvery in the raw low polar sunlight, drew away very slowly, as if he’d grown faintly disgusted with our activity. My gaze kept on turning to see the whole shimmering back of his helmet blown off in a gorgeous sickening brain-fog and blood-mist that was already falling in the vacuum as fine red snow.

A loud tock then and glove-sting as the Crusoe’s second slug hit the miniradar, but my gaze had gone back to the direction Pete had been facing when he bought it—in time to see the green needle-flash of the Crusoe’s gun in a notch in Gioja’s low wall, where the black of the shadowed rock met the gem-like starfields along a jagged border. I unslung my Swift [All-purpose vacuum rifle named for the .22 cartridge which as early as 1940 was being produced by Winchester, Remington, and Norma with factory loads giving it a muzzle velocity of 4,140 feet, almost a mile, a second.] as I dodged a long step to the side and squeezed off three shots. The first two shells must have traveled a touch too high, but the third made a beautiful fleeting violet globe at the base of the notch. It didn’t show me a figure, whole or shattered, silvery or otherwise, on the wall or atop it, but then some crusoes are camouflaged like chameleons and most of them move very fast.

Pete’s suit was still falling slowly and stiffly forward. Three dozen yards beyond was a wide black fissure, though exactly how wide I couldn’t tell because much of the opposite lip merged into the shadow of the wall. I scooted toward it like a rat toward a hole. On my third step, I caught up Pete by his tool belt and oxy tube while his falling front was still inches away from the powdered pumice, and I heaved him along with me. Some slow or over-drilled part of my brain hadn’t yet accepted he was dead.

Then I began to skim forward, inches above the ground myself, kicking back against rocky outcrops thrusting up through the dust—it was like fin-swimming. The crusoe couldn’t have been expecting this nut stunt, by which I at least avoided the dreamy sitting-duck slowness of safer, higher-bounding moon-running, for there was a green flash behind me and hurtled dust faintly pittered my soles and seat. He hadn’t been leading his target enough. Also, I knew now he had shells as well as slugs.

I was diving over the lip three seconds after skoot-off when Pete’s boot caught solidly against a last hooky outcrop. The something in my brain was still stubborn, for I clutched him like clamps, which made me swing around with a jerk. But even that was lucky, for a bright globe two yards through winked on five yards ahead like a mammoth firefly’s flash, but not quite as gentle, for the invisible rarified explosion-front hit me hard enough to boom my suit and make the air inside slap me. Now I knew he had metal-proximity fuses on some of his shells too—they must be very good at mini-stuff on his home planet.

The tail of the pale green flash showed me the fissure’s bottom a hundred yards straight below and all dust, as ninety percent of them are—pray God the dust was deep. I had time to thumb Extreme Emergency to the ship for it to relay automatically to Circumluna. Then the lip had cut me off from the ship and I had lazily fallen out of the glare into the blessed blackness, the dial lights in my helmet already snapped off—even they might make enough glow for the crusoe to aim by. The slug had switched off Pete’s.

Ten, twelve seconds to fall and the opposite lip wasn’t cutting off the notched crater wall. I could feel the Crusoe’s gun trailing me down—he’d know moon-G, sticky old five-foot. I could feel his tentacle or finger or claw or ameboid bump tightening on the trigger or button or what. I shoved Pete away from me, parallel to the fissure wall, as hard as I could. Three more seconds, four, and my suit boomed again and I was walloped as another green flash showed me the smooth-sifted floor moving up and beginning to hurry a little. This flash was a hemisphere, not a globe—it had burst against the wall—but if there were any rock fragments they missed me. And it exactly bisected the straight line between me and Pete’s silvery coffin. The crusoe knew his gun and his Luna—I really admired him, even if my shove had pushed Pete and me, action and reaction, just enough out of the target path. Then the fissure lip had cut the notch and I was readying to land like a three-legged crab, my Swift reslung, my free hand on my belted dust-shoes.

* * * *

Eleven seconds’ fall on Luna is not much more than two on earth, but either are enough to build up a velocity of over fifty feet a second. The dust jarred me hard, but thank God there were no reefs in it. It covered at least all the limbs and front of me, including my helmet-front—my dial lights, snapped on again, showed a grayness fine-grained as flour.

The stuff resisted like flour, too, as I unbelted my dust-shoes. Using them for a purchase, I pulled my other arm and helmet-front free. The stars looked good, even gray-dusted. With a hand on each shoe, I dragged out my legs and, balancing gingerly on the slithery stuff, got each of my feet snapped to a shoe. Then I raised up and switched on my headlight. I hated that. I no more wanted to do it than a hunted animal wants to break twigs or show itself on the skyline, but I knew I had exactly as long to find cover as it would take the crusoe to lope from the notch to the opposite lip of the fissure. Most of them lope very fast, they’re that keen on killing.

Well, we started the killing, I reminded myself. This time I’m the quarry.

My searchlight made a perverse point of hitting Pete’s shimmering casket, spread-eagled, seven-eighths submerged, like a man floating on his back. I swung the beam steadily. The opposite wall was smooth except for a few ledges and cracks and there wasn’t any overhang to give a man below cover from someone on top.

But a section of the wall on my side, not fifty yards away, was hugely pocked with holes and half-bubbles where the primeval lava had foamed high and big against the feeble plucking of lunar gravity. I aimed myself at the center of that section and started out. I switched off my headlight and guided myself by the wide band of starfields.

You walk dust-shoes with much the same vertical lift and low methodical forward swing as snowshoes. It was nostalgic, but hunted animals have no time for memory-delicatessen.

Suddenly there was more and redder brightness overhead than the stars. A narrow ribbon of rock along the top of the opposite wall was glaringly bathed in orange, while the rim peaks beyond glowed faintly, like smoldering volcanoes. Light from the orange ribbon bounced down into my fissure, caroming back and forth between the walls until I could dimly see again the holes I was headed for.

The crusoe had popped our ship—both tanks, close together, so that the sun-warmed gasses, exploding out into each other, burned like a hundred torches. The oxyaniline lasted until I reached the holes. I crawled through the biggest. The fading glow dimly and fleetingly showed a rock-bubble twelve feet across with another hole at the back of it. The stuff looked black, felt rough yet diamond-hard. I risked a look behind me.

The ribbon glow was darkest red—the skeleton of our ship still aglow. The ribbon flashed green in the middle— a tiny venomous dagger—and then a huge pale green firefly winked where Pete lay. He’d saved me a fourth time.

I had barely pushed sideways back when there was another of those winks just outside my hole, this one glaringly bright, its front walloping me. I heard through the rock faint tings of fragments of Pete’s suit hitting the wall, but they may have been only residual ringings, from the nearer blast, in my suit or ears.

I scrambled through the back door in the bubble into a space which I made out by crawling to be a second bubble, resembling the first even to having a back door. I went through that third hole and turned around and rested my Swift’s muzzle on the rough-scooped threshold. Since the crusoe lived around here, he’d know the territory better wherever I went. Why retreat farther and get lost? My dial lights showed that about a minute and a half had gone by since Pete bought it. Also, I wasn’t losing pressure and I had oxy and heat for four hours—Circumluna would be able to deliver a rescue force in half that time, if my message had got through and if the crusoe didn’t scupper them too. Then I got goosy again about the glow of the dial lights and snapped them off. I started to change position and was suddenly afraid the crusoe might already be trailing me by my transmitted sounds through the rock, and right away I held stock still and started to listen for him.

No light, no sound, a ghost-fingered gravity—it was like being tested for sanity-span in an anechoic chamber. Almost at once dizziness and the sensory mirages started to come, swimming in blue and burned and moaning from the peripheries of my senses—even waiting in ambush for a crusoe wouldn’t stop them; I guess I wanted them to come. So though straining every sense against the Crusoe’s approach, I had at last to start thinking about him.

It’s strange that men should have looked at the moon for millennia and never guessed it was exactly what it looked like: a pale marble graveyard for living dead men, a Dry Tortuga of space where the silver ships from a million worlds marooned their mutineers, their recalcitrants, their criminals, their lunatics. Not on fertile warm-blanketed earth with its quaint adolescent race, which such beings might harm, but on the great silver rock of earth’s satellite, to drag out their solitary furious lives, each with his suit and gun and lonely hut or hole, living by recycling his wastes; recycling, too, the bitter angers and hates and delusions which had brought him there. As many as a thousand of them, enough to mine the moon for meals and fuel-gases and to reconquer space and perhaps become masters of earth—had they chosen to cooperate. But their refusal to cooperate was the very thing for which they’d been marooned, and besides that they were of a half thousand different galactic breeds. And so although they had some sort of electronic or psionic or what-not grapevine—at least what happened to one maroon became swiftly known to the others—each of them remained a solitary Friday-less Robinson Crusoe, hence the name.

I risked flashing my time dial. Only another thirty seconds gone. At this rate it would take an eternity for the two hours to pass before I could expect aid if my call had got through, while the crusoe— As my senses screwed themselves tighter to their task, my thoughts went whirling off again.

Earthmen shot down the first crusoe they met—in a moment of fumbling panic and against all their training. Ever since then the crusoes have shot first, or tried to, ignoring our belated efforts to communicate.

* * * *

I brooded for what I thought was a very short while about the age-old problem of a universal galactic code, yet when I flashed my time dial again, seventy minutes had gone somewhere.

That really froze me. He’d had time to stalk and kill me a dozen times—he’d had time to go home and fetch his dogs!—my senses couldn’t be that good protection with my mind away. Why even now, straining them in my fear, all [ got was my own personal static: I heard my heart pounding, my blood roaring, I think for a bit I heard the Brownian movement of the air molecules against my eardrums.

What I hadn’t been doing, I told myself, was thinking about the crusoe in a systematic way.

He had a gun like mine and at least three sorts of ammo.

He’d made it from notch to fissure-lip in forty seconds or less—he must be a fast loper, whatever number feet; he might well have a jet unit.

And he’d shot at the miniradar ahead of me. Had he thought it a communicator?—a weapon?—or some sort of robot as dangerous as a man … ?

My heart had quieted, my ears had stopped roaring, and in that instant I heard through the rock the faintest scratching.

Scratch-scratch, scratch-scratch, scratch, scratch, scratch it went, each time a little louder.

I flipped on my searchlight and there coming toward me across die floor of the bubble outside mine was a silver spider as wide as a platter with four opalescent eyes and a green-banded body. Its hanging jaws were like inward-curving notched scissor blades.

I fired by automatism as I fell back. The spider’s bubble was filled with violet glare instantly followed by green. I was twice walloped by explosion-fronts and knocked down.

That hardly slowed me a second. The same flashes had shown me a hole in the top of my bubble and as soon as I’d scrambled to my feet I leaped toward it.

I did remember to leap gently. My right hand caught the black rim of the hole and it didn’t break off and I drew myself up into the black bubble above. It had no hole in the top, but two high ones in the sides, and I went through the higher one.

I kept on that way. The great igneous bubbles were almost uniform. I always took the highest exit. Once I got inside a bubble with no exit and had to backtrack. After that I scanned first. I kept my searchlight on.

I’d gone through seven or seventeen bubbles before I could start to think about what had happened.

That spider had almost certainly not been my crusoe— or else there was a troop of them dragging a rifle like an artillery piece. And it hadn’t likely been an hitherto-unknown, theoretically impossible, live vacuum-arthropod—or else the exotic biologists were in for a great surprise and I’d been right to wet my pants. No, it had most likely been a tracking or tracking-and-attack robot of some sort. Eight legs are a useful number, likewise eight hands. Were the jaws for cutting through suit armor? Maybe it was a robot pet for a lonely being. Here, Spid!

The second explosion? Either the crusoe had fired into the chamber from the other side, or else the spider had carried a bomb to explode when it touched me. Fine use to make of a pet! I giggled. I was relieved, I guess, to think it likely that the spider had been “only” a robot.

Just then—I was in the ninth or nineteenth bubble—the inside of my helmet misted over everywhere. I was panting and sweating and my dehumidifier had overloaded. It was as if I were in a real peasouper of a fog. I could barely make out the black loom of the wall behind me. I switched out my headlight. My time dial showed seventy-two minutes gone. I switched it off and then I did a queer thing.

I leaned back very carefully until as much of my suit as possible touched rock. Then I measuredly thumped the rock ten times with the butt of my Swift and held very still.

Starting with ten would mean we were using the decimal system. Of course there were other possibilities, but…

Very faintly, coming at the same rate as mine, I heard six thuds.

What constant started with six? If he’d started with three, I’d have given him one, and so on through a few more places of pi. Or if with one, I’d have given him four—and then started to worry about the third and fourth places in the square root of two. I might take his signal for the beginning of a series with the interval of minus four and rap him back two, but then how could he rap me minus two? Oh why hadn’t I simply started rapping out primes? Of course all the integers, in fact all the real numbers, from thirty-seven through forty-one had square roots beginning with six, but which one … ?

Suddenly I heard a scratching…

* * * *

My searchbeam was on again, my helmet had unmisted, my present bubble was empty.

Just the same I scuttled out of it, still trending upward where I could. But now the holes wouldn’t trend that way. They kept going two down for one up and the lines of bubbles zigzagged. I wanted to go back, but then I might hear the scratching. Once the bubbles started getting smaller. It was like being in solid black suds. I lost any sense of direction. I began to lose the sense of up-down. What’s moon-gravity to the numbness of psychosis? I kept my searchlight on although I was sure the glow it made must reach ten bubbles away. I looked all around every bubble before I entered it, especially the overhang just above the entry hole.

Every once in a while I would hear somebody saying Six! Six? Six! like that and then very rapidly seven-eight-nine-five-four-three-two-one-naught. How would you rap naught in the decimal system? That one I finally solved: you’d rap ten.

Finally I came into a bubble that had a side-hole four feet across and edged at the top with diamonds. Very fancy. Was this the Spider Princess’ boudoir? There was also a top hole but I didn’t bother with that—it had no decor. I switched off my searchlight and looked out the window without exposing my head. The diamonds were stars. After a bit I made out what I took to be the opposite lip of the fissure I’d first dove in, only about one hundred feet above me. The rim-wall beyond looked vaguely familiar, though I wasn’t sure about the notch. My time dial said one hundred eighteen minutes gone as I switched it off. Almost time to start hoping for rescue. Oh great!—with their ship a sitting duck for the crusoe they wouldn’t be expecting. I hadn’t signaled a word besides Extreme Emergency.

I moved forward and sat in the window, one leg outside, my Swift under my left arm. I plucked a flash grenade set for five seconds from my belt, pulled the fuse and tossed it across the fissure, almost hard enough to reach the opposite wall.

I looked down, my Swift swinging like my gaze.

The fissure lit up like a boulevard. Across from me I knew the flare was dropping dreamily, but I wasn’t looking that way. Right below me, two hundred feet down, I saw a transparent helmet with something green and round and crested inside and with shoulders under it.

Just then I heard the scratching again, quite close.

I fired at once. My shell made a violet burst and raised a fountain of dust twenty feet from the crusoe. I scrambled back into my bubble, switching on my searchlight. Another spider was coming in on the opposite side, its legs moving fast. I jumped for the top-hole and grabbed its rim with my free hand. I’d have dropped my Swift if I’d needed my other hand, but I didn’t. As I pulled myself up and through, I looked down and saw the spider straight below me eyeing me with its uptilted opalescent eyes and doubling its silver legs. Then it straightened its legs and sprang up toward me, not very fast but enough against Luna’s feeble gravitational tug to put it into this upper room with me. I knew it mustn’t touch me and I mustn’t touch it by batting at it. I had started to shift the explosive shell in my gun for a slug, and its green-banded body was growing larger, when there was a green blast in the window below and its explosion-front, booming my suit a little, knocked the spider aside and out of sight before it made it through the trap door of my new bubble. Yet the spider didn’t explode, if that was what had happened to the first one; at any rate there was no second green flash.

My new bubble had a top hole too and I went through it the same way I had the last. The next five bubbles were just the same too. I told myself that my routine was getting to be like that of a circus acrobat—except who stages shows inside black solidity?—except the gods maybe with the dreams they send us. The lava should be transparent, so the rim-wall peaks could admire.

At the same time I was thinking how if the biped humanoid shape is a good one for medium-size creatures on any planet, why so the spider shape is a good one for tiny creatures and apt to turn up anywhere and be copied in robots too.

The top hole in the sixth bubble showed me the stars, while one half of its rim shone white with sunlight.

Panting, I lay back against the rock. I switched off my searchlight. I didn’t hear any scratching.

The stars. The stars were energy. They filled the universe with light, except for hidey holes and shadows here and there.

Then the number came to me. With the butt of my Swift I rapped out five. No answer. No scratching either. I rapped out five again.

Then the answer came, ever so faintly. Five knocked back at me.

Six five five—Planck’s Constant, the invariant quantum of energy. Oh, it should be to the minus 29th power, of course, but I couldn’t think how to rap that and, besides, the basic integers were all that mattered.

I heard the scratching …

I sprang and caught the rim and lifted myself into the glaring sunlight … and stopped with my body midway.

Facing me a hundred feet away, midway through another top-hole—he must have come very swiftly by another branch of the bubble ladder—he’d know the swiftest ones—was my green-crested crusoe. His face had a third eye where a man’s nose would be, which with his crest made him look like a creature of mythology. We were holding our guns vertically.

We looked like two of the damned, half out of their holes in the floor of Dante’s hell.

I climbed very slowly out of my hole, still pointing my gun toward the zenith. So did he.

We held very still for a moment. Then with his gun butt he rapped out ten. I could both see and also hear it through the rock.

I rapped out three. Then, as if the black bubble-world were one level of existence and this another, I wondered why we were going through this rigamarole. We each knew the other had a suit and a gun (and a lonely hole?) and so we knew we were both intelligent and knew math. So why was our rapping so precious?

He raised his gun—I think to rap out one, to start off pi.

But I’ll never be sure, for just then there were two violet bursts, close together, against the fissure wall, quite close to him.

He started to swing the muzzle of his gun toward me. At least I think he did. He must know violet was the color of my explosions. I know I thought someone on my side was shooting. And I must have thought he was going to shoot me—because a violet dagger leaped from my Swift’s muzzle and I felt its sharp recoil and then there was a violet globe where he was standing and moments later some fragment twinged lightly against my chest—a playful ironic tap.

He was blown apart pretty thoroughly, all his constants scattered, including—I’m sure—Planck’s.

* * * *

It was another half hour before the rescue ship from Circumluna landed. I spent it looking at earth low on the horizon and watching around for the spider, but I never saw it. The rescue party never found it either, though they made quite a hunt—with me helping after I’d rested a bit and had my batteries and oxy replenished. Either its power went off when its master died, or it was set to “freeze” then, or most likely go into a “hide” behavior pattern. Likely it’s still out there waiting for an incautious earthman, like a rattlesnake in the desert or an old, forgotten land mine.

I also figured out, while waiting in Gioja crater, there near the north pole on the edge of Shackleton crater, the only explanation I’ve ever been able to make, though it’s something of a whopper, of the two violet flashes which ended my little mathematical friendship-chant with the crusoe. They were the first two shells I squeezed off at him— the ones that skimmed the notch. They had the velocity to orbit Luna, and the time they took—two hours and five minutes—was right enough.

Oh, the consequences of our past actions!