Chasm City

by Alastair Reynolds

  Sky was thinking about that when Gomez called him again. The urgency in his voice was obvious despite the weakness of the signal.

  "Sky. Bad news. The two shuttles have launched a pair of drones. They might just be cameras, but my guess is they'll have anti-collision warheads on them. They're on high-gee trajectories and they'll reach us in about fifteen minutes."

  "They wouldn't do it," Norquinco said. "They wouldn't attack us without first finding out what's going on here. They'd run the risk of destroying a whole Flotilla ship which has, um, survivors and supplies on it, just like we thought it would have."

  "No," Sky said. "They'd do it-if only to stop us getting hold of whatever they think's on her."

  "I don't believe it."

  "Why not? It's exactly what I'd do."

  He told Gomez to sit tight and killed the link. The fraction of a day he had imagined they would have to themselves had now compressed down to less than a quarter of an hour. It was probably not enough time to make it back to the shuttle and get away, even if there had been no obstructions to cut through. But there was still time to do something. Time, in fact, to hear the rest of what Travelling Fearlessly had to say. It might make all the difference. Trying not to think of the minutes ticking away, and the missiles haring closer, he told the grub to continue his story.

  The grub was happy to oblige.

  "Gideon," the man in the chair said, after he had curtailed the telling of his story with an abrupt sequence of commands.

  We had arrived in a natural cavern, high up on one side of a concave rock face. There was a ledge here, large enough to accommodate the wheelchair. I thought of pushing Ferris over the edge, but there was a sturdy-looking safety rail, uninterrupted except for a point where it allowed entrance to a caged spiral staircase that led all the way down to the chamber's floor.

  "Fuck," Quirrenbach said, looking over the edge.

  "You're getting the hang of it," I said.

  I would have been as shocked as Quirrenbach, I suppose-except that I'd been forewarned by what Sky had found inside the Caleuche . There was another maggot down there-bigger even than the one Sky had seen, I thought-but it was alone; there were no helper grubs with it.

  "This wasn't quite what I was expecting," Zebra said.

  "It's not what anyone's ever expecting," the man in the chair said.

  "Someone please tell me what the fuck that thing is," Quirrenbach said, like someone hanging very grimly onto the last tattered shred of sanity.

  "Much what it looks like," I said. "A large alien creature. Intelligent, too, in its own special way. They call themselves the grubs."

  Quirrenbach spoke through clenched jaw, the words emerging one at a time. "How. Do. You. Know."

  "Because I had the pleasure of meeting one before."

  "When?" Zebra asked.

  "A long, long time ago."

  Quirrenbach sounded like a man on the edge of a nervous breakdown. "You're losing me, Tanner."

  "Believe me, I'm not quite sure I believe it all myself." I nodded at Ferris. "You and him-the maggot-you have quite a relationship going, don't you?"

  The chair clattered. "It's really rather simple. Gideon gives us something we need. I keep Gideon alive. What could be fairer than that?"

  "You torture it."

  "Sometimes he needs encouragement, that's all."

  I looked down at the maggot again. It rested in a metal enclosure, a steep-sided bath that was knee-deep in brackish dark fluid, like squid ink. He was chained in place, and all around him loomed scaffolding and catwalks. Obscure, industrial-looking machines waited on gantries to be moved over the maggot. Electrical cables and fluid lines plunged into him at various points along his length.

  "Where did you find him?" Zebra said.

  "Here, as it happens," Ferris told her. "He was inside the remains of a ship. It had crashed here, at the base of the chasm, maybe a million years ago. A million years. But that's nothing to him. Though damaged and incapable of flight, the ship had kept him alive, in semi-hibernation, for all that time."

  "It just crashed here?" I said.

  "There was more to it than that. It was running away from something. What, I've never really found out."

  I interrupted the sequence of sounds emanating from the chair. "Let me guess. A race of sentient, killer machines. They'd been attacking his race-and others-for millions of years themselves; harrying them from star to star. Eventually the grubs were pushed back into interstellar space, cowering away from starlight. But something must have driven this one here-a spying mission or something."

  He punched a new statement into the chair, which piped, "How would you know all this?"

  "Like I just told Quirrenbach: me and the maggots go back a long, long way."

  I retrieved Sky's memory of what his grub had told him. The fugitive species learned that to survive at all they had to hide, and hide expertly. There were pockets of space where intelligence had not arisen in recent times-sterilised by supernova explosions, or neutron star mergers-and these cleansed zones made the best hiding places. But there were dangers. Intelligence was always waiting to emerge; new cultures were always evolving and spilling into space. It was these outbreaks of life which drew the predatory machines. They placed automated watching devices and traps around promising solar systems, ready to be triggered as soon as new spacefaring cultures stumbled upon them. So the grubs and their allies-the few that remained-grew intensely paranoid and watchful for the signs of new life.

  The grubs had never really paid much attention to Earth's system. Curiosity was still something that required an effort of will for them, and it was not until the signs of intelligence around Earth became blatant that the grubs forced themselves to become interested. They watched and waited to see if the humans would make any forays into interstellar space, and for centuries, and then thousands of years, nothing happened.

  But then something did happen, and it was not auspicious.

  What Ferris had learned from Gideon dovetailed exactly with what Sky had learned aboard the Caleuche . Ferris's grub had been chased for hundreds of light years-across centuries of time-by a single pursuing enemy. The enemy machine moved faster than the grub ship, able to make sharper turns and steeper decelerations. The enemy made the grubs' mastery of momentum and inertia look hamfisted in the extreme. Yet, fast and strong as the killing machines were, they had limitations-it might have been more accurate to call them blindspots-which the grubs had carefully documented over the millennia. Their techniques of gravitational sensing were surprisingly crude for such otherwise efficient killers. Grub vessels had sometimes survived attacks by hiding themselves near-or within-larger camouflaging masses.

  Finding the yellow world, with the killing machine closing on him fast, Gideon had seen his chance. He had located the deep geologic feature with an emotion as close to blessed joy as his neurophysiology allowed.

  On the approach, the enemy had engaged him with long-range weapons. But the grub had hidden his ship behind the planet's moon, the salvo of antimatter slugs gouging a chain of craters across the moon's surface. The grub had waited until the moon's position allowed him to make a rapid, unseen descent into the atmosphere and then into the chasm, the potential hideaway he had already scouted from space. He had enlarged and deepened it with his own weapons, burrowing further and further into the world's crust. Fortunately, the thick, poisonous atmosphere camouflaged most of his efforts. But on the way in he had made a terrible error, brushing the sheer walls with his projected skein of armouring force. A billion tonnes of rubble had come crashing down, entombing him when he had meant only to hide until the killing machine moved on to seek another target. He had expected to wait perhaps a thousand years, at the longest-an eyeblink in grub terms.

  It had been considerably longer than that before anyone came.

  "He must have wanted you to find him," I said.

  Ferris answered, "Yes. By then he figured the enemy must have moved on. He was using the ship t
o signal his presence, altering the ratios of gases in the chasm. Warming them, too. He was sending out other signals too-exotic radiation. But we didn't even detect that."

  "I don't think the other grubs did either."

  "For a long time, I think they kept in touch. I found something in his ship-something that didn't seem to be part of it, intact where all else showed signs of great antiquity and loss of function. It was like a glittering dandelion ball about a metre wide, just floating in its own chamber, suspended in a cradle of force. Quite beautiful and mesmerising to look at."

  "What was it?" Zebra asked.

  He had anticipated her question. "I tried to find out for myself, but the results I got-based on the extremely crude and limited tests I was capable of running-were contradictory; paradoxical. The thing seemed to be astonishingly dense; capable of stopping solar neutrinos dead in their tracks. The way it distorted light-rays around itself suggested the presence of an immense gravitational field-yet there was nothing. It simply floated there. You could almost reach out and touch it, except that there was a barrier all around it that made your fingers tingle." All the while that he had been speaking, Ferris had been entering another sequence of commands into his chair, his fingers moving with the effortless speed of an arpeggiating pianist. "I did eventually learn what it was, of course, but only by persuading the grub to tell me."

  "Persuasion?" I said.

  "He has what we may think of as pain receptors, and regions of his nervous system that produce emotional reactions analogous to fear and panic. It was only a matter of locating them."

  "So what was it?" Zebra asked.

  "A communicational device, but a very singular one."

  "Faster than light?"

  "Not quite," he answered me, after the usual pause. "Certainly not in the sense that you'd recognise it. It doesn't transmit or receive information at all. It-and its brethren aboard other grub vessels-don't need to. They already contain all the information which ever would have been received."

  "I'm not sure I understand," I said.

  "Then let me rephrase what I've just said," Ferris said, who must have had a reply already queued up. "Each and every one of their communicational devices already contains every message that would ever need to be communicated to the vessel in question. The messages are locked inside it, but are inaccessible until the scheduled moment of release. Somewhat in the manner of sealed orders on an old-time sailing ship."

  "I still don't follow," I said.

  Zebra nodded. "Me neither."

  "Listen." The man-with what must have been considerable expenditure of effort-leaned forward in his seat. "It's really very simple. The grubs retain a record of every message they would have sent, across all their racial history. Then, deep in their future-deep in what is still our future-they merge the records into something . What, I've never really understood-just that it's some kind of hidden machinery distributed throughout the galaxy. I confess the details have always eluded me. Only the name is clear, and even then the translation is probably no more than approximate." He paused, eyeing us all with his peculiarly cold eyes. "Galactic Final Memory. It is-or will be-some kind of vast, living archive. It exists now, I think, only in partial form: a mere skeleton of what it will be, millions or billions of years from now. The point, nonetheless, is simple. The archive-whatever it is-transcends time. It keeps in touch with all the past and future versions of itself, down to the present epoch and deeper into our past. It's constantly shuffling data and up and down, running endless iterations. And the grubs' communicational device is, as near as I understand it, a chip off the old block. A tiny fragment of the archive, carrying only time-tagged messages between the grubs and a handful of allied species."

  "What's to stop the grubs reading messages earlier than they were sent, and figuring out how to avoid future events?"

  Again, Ferris had seen that one coming. "They can't. The device's messages are all encoded-without the key, you can't get at them. That's the clever part. The key itself, so far as the grub understood it, would appear to be the instantaneous gravitational background radiation of the universe. When the grubs put a message into the communicational device-this is how they store them, as well-the device senses the gravitational heartbeat of the universe-the ticks of pulsars spiralling towards each other; the low moans of distant black holes devouring stars at the hearts of galaxies. It hears them all, and creates a unique signature: a key with which it encrypts the incoming message. Every device carries those messages, but they can't be read out until the device satisfies itself that the gravitational background is the same. Or nearly the same-it has allowed for the spatial position of the message recipient, of course. That gives the devices an effective range of a few thousand light-years, apparently-once they get separated beyond that distance, they just don't recognise the background signature as being correct any more. And any attempt to fake that background, to try and predict what the future gravitational signature of the universe will be like, based on the known contributions-well, it never seems to work. The devices just fold up and die, apparently."

  For centuries, then, the grub must have been able to keep in some kind of contact with its remote allies. Then it had begun to approach the message-store limit of its own communicational device and had begun to transmit only sparingly. The enemy, it was said, had access to those messages as well-their own copies of the devices-so there was always a danger in using them. The creature had imagined that it had been lonely before, when it was being chased, but now it began to understand that it had never really known solitude. Solitude was a hard crushing force, akin to the mountains of rock above it. Yet it had stayed sane, allowing itself to talk to its allies every few tens of years, maintaining a fragile sense of kinship, that it still played a small role in the greater arena of grub affairs.

  But Ferris had removed the grub from its ship, severing it with the communicational device. That must have been the start of the creature's true descent into grub madness.

  "You milk it, don't you?" I said. "Milk it for Dream Fuel. And more than that. You use its terror and loneliness. You distil those impressions and sell them."

  Ferris piped, "We've got probes sunk into his brain, reading his neural patterns. Run them through some software up in the Rust Belt, and we get to distil it into something a human can just about handle."

  "What's he talking about?" Zebra asked.

  "Experientials," I said. "The black kind, with a small maggot motif near the top. I tried one, as a matter of fact. I didn't know quite what to expect."

  "I've heard of them," Zebra said. "But I've never tried one, and I wasn't even sure they weren't an urban myth."

  "No, they're for real." I remembered the welter of emotions that the experiential had fed into my brain, when I'd tried it aboard the Strelnikov . The predominant feelings had been of awful, crushing claustrophobia and fear-yet underpinned with the gut-churning sense that no matter how oppressive the claustrophia was, it was preferable to the predator-haunted void beyond. I could still taste the terror that the experiential had instilled in me; subtly alien in flavour, yet recognisable for all that. At the time I'd had trouble understanding why people would pay to experience something like that, but now it all made much more sense. It was all about extremes of experience; anything that would blunt boredom's edge.

  "What does he get for doing it?" Zebra asked.

  "Relief," said Ferris.

  I saw what he meant. Down in the black slime which filled the tank, grey-suited workers were sloshing around with what looked like huge cattle-prods. They were knee-deep in the black stuff. Now and then one of them would run the tip of his prod across the grey side of the maggot, causing a shiver of pain to run along its blimplike length. Pale red stuff squirted out of pores in his mottled silvery skin. One of the workers moved to catch it in a flask.

  At the other end, a high, shrill squeal sounded from his mouth parts.

  "I guess he isn't making Dream Fuel like he used to," I said, feelin
g sickened. "What is it? Some kind of organic machinery?"

  "I suppose so," Ferris answered, managing to convey the minimum of interest as he did so. "He brought the Melding Plague here, after all."

  "Brought it?" Zebra said. "But he's been here thousands of years."

  "Yes. And for all that time he was dormant, until we arrived, scurrying around on the surface with our pathetic little settlements and cities."

  "Did he know he had it?" I asked.

  "I very much doubt it. The plague was probably something he carried without even knowing it; an old infection to which he had long since adapted. Dream Fuel might have been only slightly younger; a protection they evolved or engineered for themselves: a living stew of microscopic machines constantly secreted by their bodies. The machines were immune to the plague and held it in check, but they did much more than that. They healed and nourished their host, conveyed information to and from his secondary grubs . . . eventually, I think, it became so much a part of them that they could no longer have lived without it."

  "But somehow the plague reached the city," I said. "How long have you been down here, Ferris?"

  "The better part of four interminable centuries, ever since I discovered him. The plague meant nothing to me, of course-I had nothing in me that it could harm. Conversely, his Dream Fuel-his very blood-kept me alive, without access to any other life-extension procedures." He fingered the silver blanket over his frame. "Of course, the ageing process has not been totally arrested. Fuel is beneficial, but it is emphatically no miracle cure."

  I asked, "Then you've never seen Chasm City?"

  "No-but I know what happened." He looked hard at me; I felt my body temperature drop under the scrutiny of his gaze. "I prophesied it. I knew it would happen; that the city would turn monstrous and fill itself with demons and ghouls. I knew that our cleverest, swiftest and tiniest machines would turn against us; corrupting minds and flesh; bringing forth perversities and abominations. I knew there would come a time when we would have to turn to simpler machines; to older and cruder templates." He raised a finger, accusingly. "All this I foresaw. Do you imagine that I engineered this chair in a mere seven years?"