Chasm City

by Alastair Reynolds

  By any strict definition, there were no creatures on Sky's Edge that were exactly reptilian. Reptiles, even on Earth, were only one possible evolutionary outcome from a vast range of possibilities.

  The largest invertebrates on Earth had been squid, but on Sky's Edge, invertebrate forms had invaded land as well. No one really knew why life had gone down this road, but the best guess was that some catastrophic event had made the oceans shrink to perhaps half their previous area, exposing vast new areas of dry ground. Life on the ocean fringes had been given a huge incentive to adapt to land. The backbone had just never been invented, and through slow, fumbling, mindless ingenuity, evolution had managed to do without it. Life on Sky's Edge was genuinely spineless. The largest animals-the hamadryads-maintained structural rigidity through the pressure of circulatory fluids alone, pumped by hundreds of hearts spread throughout the creature's volume.

  But they were cold-blooded, regulating their body temperatures by their surroundings. There had never been a winter on Sky's Edge; nothing to select for mammal-like creatures. It was that cold-bloodedness which was most evocative of the reptilian. It meant that Sky's Edge animals moved slowly, feeding infrequently, and lived to great ages. The largest of them, the hamadryads, did not even die in any familiar sense. They simply changed.

  The connecting corridor opened out into the largest of the basement chambers, where we kept the juvenile. Originally this area had been intended for a family of crocodiles, but they were on ice for now. The entire display area which they had been assigned was just barely large enough for the young hamadryad. Fortunately, it had not grown perceptibly bigger in its time in captivity, but we would certainly have to build a huge new chamber if Cahuella was serious about bagging a near-adult.

  It was some months since I had seen the juvenile. Frankly, it did not interest me greatly. Eventually it dawned on one that the creature did not actually do very much. Its appetite was negligible once it had fed. Typically, it would curl up and enter a state not far from death. Hamadryads had no real predators so they could afford to digest their food and conserve energy in peace.

  Now we overlooked the deep white-walled pit which had been originally intended for the crocs. Rodriguez, one of my men, was leaning over the side, sweeping the bottom with a ten-metre-long broom. That was how far below us the floor was, surrounded by sheer walls in white ceramic. Sometimes Rodriguez had to go into the pit to fix something, a task I never greatly envied him, even when the juvenile was on the other side of a barrier. There were just some places in life where it was best not to be, and a snake pit was one of them. Rodriguez grinned at me beneath his moustache, hauling the broom out and racking it on the wall behind him, along with an array of similarly long-handled tools: claws, anaesthetic harpoons, electrical prods and such like.

  "How was your trip to Santiago?" I said. He had been down there on business for us, exploring new lines of trade.

  "Glad to be back, Tanner. The place is full of aristocratic arseholes. They talk about indicting the likes of us for war crimes and at the same time they hope the war never ends because it adds some colour to their miserable rich lives."

  "Some of us they already have indicted," Cahuella said.

  Rodriguez picked leaves from the broom's bristles. "Yeah, I heard. Still, this year's war criminal is next year's saviour of the people, right? Besides-we all know guns don't kill people, do they?"

  "No, it's the small metal projectiles that generally do the killing," Cahuella said, smiling. He fingered the cattle-prod lovingly, perhaps remembering the time he had used it to shepherd the juvenile into its transport cage. "How is my baby, anyway?"

  "I'm a little worried about that skin infection. Do these things moult?"

  "I don't think anyone knows. We'll probably be the first to find out if they do." Cahuella leaned over the wall-it was waist height-and looked down into the pit. It looked unfinished. Here and there were a few sparse attempts at vegetation, but we had quickly discovered that the hamadryad behaviour appeared to have very little to do with its surroundings. It breathed and smelled prey and occasionally ate. Otherwise it just lay coiled like the hawser of a vast maritime ship.

  Even Cahuella had become bored with it after a while-after all, it was just a juvenile: he would be dead long before it grew to anything near its adult size.

  The hamadryad wasn't visible. I leaned over the edge, but it was obviously nowhere in the pit itself. There was an alcove, cool and dark, set into the wall beneath us; that was where the thing could usually be found when it was sleeping.

  "She's asleep," Rodriguez said.

  "Yeah," I said. "Come back in a month and maybe it'll have moved."

  "No," Cahuella said. "Take a look at this."

  There was a white metal box set on our side of the wall; I hadn't noticed it before. He flipped open a lid on the box and removed something like a walkie-talkie: a control pad with an aerial and a matrix of controls set into it.

  "You're not serious, are you?"

  Cahuella stood with his legs slightly apart, the control unit in one hand. With his other hand he jabbed hesitantly at the matrix of buttons, as if not quite certain of the sequence he should be entering. But whatever he did had some effect: I heard the unmistakable dry slithering of the uncoiling snake below us. It was a sound like a sheet of tarpaulin being dragged over concrete.

  "What's happening?"

  "Have a guess." He was enjoying himself, leaning over the edge and watching the creature emerge from its hideaway.

  The hamadryad might well have been a juvenile, but it was still as large as any I wanted to be this close to. The snakelike body was twelve metres long, as thick as my torso for most of that length. It moved like a snake, of course: there was really only one way for a long, limbless predator to move, especially one that weighed more than a tonne. The body was textureless, almost bloodlessly pale, for the creature was adjusting its skin coloration to match the white walls of the chamber. They had no predators, but they were masters of ambush.

  The head was eyeless. No one was exactly sure how the snakes managed that trick of camouflaging themselves when they were blind, but there must have been optical organs distributed around the skin, purely to serve the coloration function and not wired into the higher nervous system at all. Not that they were truly blind, either, for the hamadryad did have a set of eyes, with remarkable acuity, spaced apart for binocular vision. But the eyes were set inside the upper roof of its jaw, analogous to the heat sensors in the mouth of a venomous snake. It was only when the animal opened its mouth to strike that it saw anything of the world. By then a host of other senses-infrared and smell, mainly-would have ensured that it had locked onto likely prey. The jaw-mounted eyes were only there to guide the final moments of the attack. It sounded deeply alien, but I had heard of a mutation in frogs which caused the eyes to grow inside the mouth, with no serious impact on the frog's well-being. It was also the case that terrestrial snakes functioned almost as well blind as sighted.

  Now it stopped. It had emerged fully from the alcove, lightly coiled around itself.

  "Well?" I said. "That's a nice trick. Are you going to tell me how it's done?"

  "Mind control," Cahuella said. "Doctor Vicuna and I drugged it and did a little neural experimentation."

  "The ghoul's been here again?"

  Vicuna was the resident veterinarian. He was also an ex-interrogation specialist with a past that was rumoured to harbour a number of war crimes involving medical experiments on prisoners.

  "The ghoul is an expert in methods of neural regimentation. It was Vicuna who mapped the major control nodes of the hamadryad's rather rudimentary central nervous system. Vicuna who developed the simple electrical-stimulation implants which we emplaced at strategic positions throughout what I rather charitably refer to as the creature's brain."

  He told me they had experimented with these implants until they could coax a simple series of behaviour patterns out of the snake. There was nothing too subtle abo
ut it, either-the snake's behaviour patterns were simple to begin with. A hamadryad, no matter how large it grew, was basically a hunting machine with a few quite simple subroutines. It was the same with the crocodiles, until we put them on ice. They were dangerous, but easy to work with once you understood how their minds worked. The same stimulus always gave the same result with crocs. The hamadryad's routines were different-honed to life on Sky's Edge-but not much more complex.

  "All I did was hit the node that tells the snake it's time to wake up and find some food," Cahuella said. "It doesn't really need to feed, of course-we fed it a live goat a week ago-but its little brain doesn't remember that."

  "I'm impressed." I was, but I was also uncomfortable. "What else can you get it to do?"

  "This is a good one. Watch."

  He jabbed at a control and the hamadryad moved with whiplash speed towards the wall. The jaws opened at the last instant, the blunt head smacking into the ceramic tiles with tooth-shattering force.

  The snake, stunned, retreated into a coil.

  "Let me guess. You just made it think it had seen something worth eating."

  "It's child's play," Rodriguez said, smiling at the demonstration. Evidently he had seen something of it before.

  "Look," Cahuella said. "I can even make it go back to its hole."

  I watched the snake gather itself and neatly insert itself into the alcove again, until the last of its thigh-thick coils had slipped from view.

  "Any point to this?"

  "Yeah, of course." His look at me was one of acute disappointment, that I had not grasped this sooner. "A brain of a near-adult hamadryad isn't any more complicated than this one. If we can catch ourselves a big one, we can drug it while we're still out in the jungle. We know what tranquillisers work on snake biochemistry from our work on the juvenile. Once the thing's out cold, Vicuna can climb up and implant the same hardware, rigged to another control unit like this one. Then all we've got to do is point the snake towards the Reptile House and tell it there's food in front of its nose. It'll slither all the way home."

  "Through a few hundred kilometres of jungle?"

  "What's to stop it? If the thing starts showing signs of malnutrition, we feed it. Otherwise, we just let the bastard slither-isn't that right, Rodriguez?"

  "He's right, Tanner. We can follow it in our vehicles; protect it from any other hunters who might want to take a pot at it."

  Cahuella nodded. "And when it gets here we park it in a new snakepit and tell it to curl up and sleep for a while."

  I smiled, reaching for an obvious technical objection-and came back empty-handed. It sounded insane, but when I tried to pick a hole in any single aspect of it, Cahuella's plan was difficult to fault. We knew enough about the behaviour of near-adults to at least have a good idea where to begin hunting one, and we could increase our tranquilliser dosages accordingly, multiplying by the ratio of body volumes. We would also have to scale up our needles-they would need to be more like harpoons now, but again, that was within our capabilities. Somewhere in his cache of weapons, Cahuella was bound to have harpoon guns.

  "We'll still need to dig a new pit," I said.

  "Get your men working on it. They can have it ready by the time we get back."

  "Reivich is just a detail in all this, isn't he? Even if Reivich turned back tomorrow, you'd still find an excuse to go up there and look for your adult."

  Cahuella sealed the control box away and leaned with his back to the wall, studying me critically. "No. What do you think I am, some kind of obsessive? If it meant that much to me, we'd have been up there already. I'm just saying it'd be stupid to waste an opportunity like this."

  "Two birds with one stone?"

  "Two snakes," he said, with careful emphasis on the last word. "One literally, one metaphorically."

  "You don't really think of Reivich as a snake, do you? In my book he's just a scared rich kid doing what he thinks is right."

  "What do you care what I think?"

  "I think we need to be clear about what's driving him. That way we understand him and can predict his actions."

  "What does it matter? We know where the kid's going to be. We set the ambush and that's that."

  Beneath us, the snake rearranged itself. "Do you hate him?"

  "Reivich? No. I pity him. Sometimes I even think I might sympathise with him. If he was going up against anyone else because they'd killed his family-which, incidentally, I did not do-I might even wish him the best of luck."

  "Is he worth all this?"

  "You got an alternative in mind, Tanner?"

  "We could deter him. Hit first and take out a few of his men, just to demoralise him. Maybe even that wouldn't be necessary. We could just set some kind of physical barrier-start a forest fire, or something. The monsoons won't arrive for a few weeks. There must be a dozen other things we could do. The kid doesn't necessarily have to die."

  "No; that's where you're wrong. No one goes up against me and lives. I don't give a shit if they've just buried their whole family and their fucking pet dog. It's a point I'm making, understand? If we don't make it now, we'll have to make it over and again in the future, every time some aristocrat cocksucker starts feeling lucky."

  I sighed, seeing that this was not an argument I was going to win. I had known it would come to this: that Cahuella would not be talked out of his hunting expedition. But I had felt some show of disagreement was necessary. I was senior enough in his employment that I was almost obliged to question his orders. It was part of what he paid me for: to play his conscience in the moments when he searched for his own and found only an abscessive hole where one had been.

  "But it doesn't have to be personal," I said. "We can take out Reivich cleanly, without turning it into some kind of recriminatory bloodbath. You thought you were joking when you said I went for specific areas of brain function when I shot people in the head. But you weren't. I can do that, if it suits the situation." I thought of the soldiers on my own side I had been forced to assassinate; innocent men and women whose deaths served some inscrutable higher plan. Though it was no kind of absolution from the evil that I had perpetrated, I had always tried to take them out as quickly and painlessly as my expertise allowed. I felt-then-that Reivich deserved something of the same kindness.

  Now, in Chasm City, I felt something else entirely.

  "Don't worry, Tanner. We'll make it nice and quick on him. A real clinical job."

  "Good. I'll be hand-picking my own team, of course . . . is Vicuna coming with us?"

  "Of course."

  "Then we'll need two tents. I'm not eating from the same table as the ghoul, no matter what tricks he's learned to do with snakes."

  "There'll be more than two tents, Tanner. Dieterling'll be with us, of course-he knows snakes better than anyone-and I'm taking Gitta as well."

  "There's something I want you to understand," I said. "Just going up into the jungle carries some risk. The instant Gitta leaves the Reptile House, she's automatically in greater danger than if she remained. We know some of our enemies keep a close watch on our movements, and we know there are things in the jungle that are best avoided." I paused. "I'm not abdicating responsibility, but I want you to know I can't guarantee anyone's safety on this expedition. All I can do is my best-but my best might not be good enough."

  He patted me on the shoulder. "I'm sure your best will suffice, Tanner. You've never let me down before."

  "There's always a first time," I said.

  Our small hunting convoy consisted of three armoured ground-effect vehicles. Cahuella, Gitta and I rode in the lead vehicle, along with Dieterling. He had his hands on the joystick, guiding us expertly along the overgrown trail. He knew the terrain and was also an expert on hamadryads. It hurt me to think he was dead as well now.

  Behind, Vicuna and three other security people rode in the second vehicle: Letelier, Orsono and Schmidt; all with expertise in deep-country work. The third vehicle carried heavy weapons-amongst them the ghoul's
harpoon guns-together with ammunition, medical supplies, food and water rations and our deflated bubbletents. It was driven by one of Cahuella's old trustees, while Rodriguez rode shot-gun in the rear, sweeping the path in case anyone tried to attack us from behind.

  On the dashboard was a map of the Peninsula divided into grid sections, with our current position marked by a pulsing blue dot. Several hundred kilometres to the north, but on what would eventually become the same track as us, was a red pulse which moved a little south each day. That was Reivich's squad; thinking they were moving covertly, but betrayed by the signatures of their weapons which Orcagna was tracking. They made about fifty or sixty kilometres a day, which was about as good a rate as anyone was capable of maintaining through the jungle. Our plan was to set up camp a day's travel south of Reivich.

  In the meantime, we were passing through the lower extent of the hamadryad range. You could see the excitement in Cahuella's eyes as he peered deep into the jungle for a hint of large, slow movement. Near-adults moved so ponderously-and were so invulnerable to any kind of natural predation-that they had never evolved any flight response. The only thing that made a hamadryad move was hunger or the migratory imperative of their breeding cycle. Vicuna said they did not even have what we would think of as a survival instinct. They had no more need of one than a glacier did.

  "There's a ham tree," Dieterling said, towards the end of the day. "Newly fused, by the look of it." He pointed off to one side, into what looked like impenetrable gloom. My eyesight was good, but Dieterling's was apparently superhuman.