The Revelation Space Collection (470 page)

The entire procedure lasted six minutes. Outside, Vargovic followed a slitherwalk to the city zoo, and then barged through crowds of schoolchildren until he arrived at the aquarium where Cholok was meant to meet him. The exhibits were devoted to Europan biota, most of which depended on the ecological niches of the hydrothermal vents, carefully reproduced here. There was nothing very exciting to look at, since most Europan predators looked marginally less fierce than hat stands or lampshades. The commonest were called ventlings: large and structurally simple animals whose metabolisms hinged on symbiosis. They were pulpy, funnelled bags planted on a tripod of orange stilts, moving with such torpor that Vargovic almost nodded off before Cholok arrived at his side.

She wore an olive-green coat and tight emerald trousers, projecting a haze of medicinal entoptics. Her clenched jaw accentuated the dourness he had gleaned from the intercept.

They kissed.

‘Good to see you Marius. It’s been - what?’

‘Nine years, thereabouts.’

‘How’s Phobos these days?’

‘Still orbiting Mars.’ He deployed a smile. ‘Still a dive.’

‘You haven’t changed.’

‘Nor you.’

At a loss for words, Vargovic found his gaze returning to the informational read-out accompanying the ventling exhibit. Only half-attentively, he read that the ventlings, motile in their juvenile phase, gradually became sessile in adulthood, stilts thickening with deposited sulphur until they were rooted to the ground like stalagmites. When they died, their soft bodies dispersed into the ocean, but the tripods remained; eerily regular clusters of orange spines concentrated around active vents.

‘Nervous, Marius?’

‘In your hands? Not likely.’

‘That’s the spirit.’

They bought two mugs of mocha from a nearby servitor, then returned to the ventling display, making what sounded like small talk. During indoctrination, Cholok had been taught Phrase-Embedded Three. The code allowed the insertion of secondary information into a primary conversation by means of careful deployment of word order, hesitation and sentence structure.

‘What have you got?’ Vargovic asked.

‘A sample,’ Cholok answered, one of the easy, pre-set words that did not need to be laboriously conveyed. But what followed took nearly five minutes to put over, freighted via a series of rambling reminiscences of the Phobos years. ‘A small shard of hyperdiamond. ’

Vargovic nodded. He knew what hyperdiamond was: a topologically complex interweave of tubular fullerene; structurally similar to cellulose or bulk chitin but thousands of times stronger; its rigidity artificially maintained by some piezoelectric trick that Gilgamesh lacked.

‘Interesting,’ Vargovic said. ‘But unfortunately not interesting enough.’

She ordered another mocha and downed it, replying, ‘Use your imagination. Only the Demarchy knows how to synthesise it.’

‘It’s also useless as a weapon.’

‘Depends. There’s an application you should know about.’

‘What?’

‘Keeping this city afloat - and no, I’m not talking about economic solvency. Do you know about Buckminster Fuller? He lived about four hundred years ago; believed absolute democracy could be achieved through technological means.’

‘The fool.’

‘Maybe. But Fuller also invented the geodesic lattice that determines the structure of the buckyball: the closed allotrope of tubular fullerene. The city owes him on two counts.’

‘Save the lecture. How does the hyperdiamond come into it?’

‘Flotation bubbles,’ she said. ‘Around the outside of the city. Each one is a hundred-metre-wide sphere of hyperdiamond, holding vacuum. A hundred-metre-wide molecule, in fact, since each sphere is composed of one endless strand of tubular fullerene. Think of that, Marius: a molecule you could park a ship inside.’

While he absorbed that, another part of his mind continued to read the ventling caption: how their biochemistry had many similarities with the gutless tube worms that lived around Earth’s ocean vents. The ventlings drank hydrogen sulphide through their funnels, circulating it via a modified form of haemoglobin, passing it through a bacteria-saturated organ in the lower part of their bags. The bacteria split and oxidised the hydrogen sulphide, manufacturing a molecule similar to glucose. The glucose-analogue nourished the ventling, enabling it to keep living and occasionally make slow perambulations to other parts of the vent, or even to swim between vents, until the adult phase rooted it to the ground. Vargovic read this, and then read it again, because he had just remembered something: a puzzling intercept passed to him from cryptanalysis several months earlier; something about Demarchy plans to incorporate ventling biochemistry into a larger animal. For a moment he was tempted to ask Cholok about it directly, but he decided to force the subject from his mind until a more suitable time.

‘Any other propaganda to share with me?’

‘There are two hundred of these spheres. They inflate and deflate like bladders, maintaining C-A’s equilibrium. I’m not sure how the deflation happens, except that it’s something to do with changing the piezoelectric current in the tubes.’

‘I still don’t see why Gilgamesh needs it.’

‘Think. If you can get a sample of this to Ganymede, they might be able to find a way of attacking it. All you’d need would be a molecular agent capable of opening the gaps between the fullerene strands so that a molecule of water could squeeze through, or something that impedes the piezoelectric force.’

Absently Vargovic watched a squid-like predator nibble a chunk from the bag of a ventling. The squid’s blood ran thick with two forms of haemoglobin, one oxygen-bearing, one tuned for hydrogen sulphide. They used glycoproteins to keep their blood flowing and switched metabolisms as they swam from oxygen-dominated to sulphide-dominated water.

He snapped his attention back to Cholok. ‘I can’t believe I came all this way for . . . what? Carbon?’ He shook his head, slotting the gesture into the primary narrative of their conversation. ‘How did you obtain this?’

‘An accident, with a gilly.’

‘Go on.’

‘An explosion near one of the bubbles. I was the surgeon assigned to the gilly; had to remove a lot of hyperdiamond from him. It wasn’t difficult to save a few splinters.’

‘Forward-thinking of you.’

‘Hard part was persuading Gilgamesh to send you. Especially after Maunciple—’

‘Don’t lose any sleep over him,’ Vargovic said, consulting his coffee. ‘He was a fat bastard who couldn’t swim fast enough.’

The surgery took place the next day. Vargovic woke with his mouth furnace-dry.

He felt . . . odd. They had warned him of this. He had even interviewed subjects who had undergone similar procedures in Gilgamesh’s experimental labs. They told him he would feel fragile, as if his head was no longer adequately coupled to his body. The periodic flushes of cold around his neck only served to increase that feeling.

‘You can speak,’ Cholok said, looming over him in surgeon’s whites. ‘But the cardiovascular modifications - and the amount of reworking we’ve done to your laryngeal area - will make your voice sound a little strange. Some of the gilled are really only comfortable talking to their own kind.’

He held a hand before his eyes, examining the translucent webbing that now spanned between his fingers. There was a dark patch in the pale tissue of his palm: Cholok’s embedded sample. The other hand held another.

‘It worked, didn’t it?’ His voice sounded squeaky. ‘I can breathe water.’

‘And air,’ Cholok said. ‘Though what you’ll now find is that really strenuous exercise only feels natural when you’re submerged. ’

‘Can I move?’

‘Of course,’ she said. ‘Try standing up. You’re stronger than you feel.’

He did as she suggested, using the moment to assess his surroundings. A neural monitor clamped his crown. He was naked, in a brightly lit revival room; one glass-walled side faced the exterior ocean. It was from here that Cholok had first contacted Gilgamesh.

‘This place is secure, isn’t it?’

‘Secure?’ she said, as if the word itself was obscene. ‘Yes, I suppose so.’

‘Then tell me about the Denizens.’

‘What?’

‘Demarchy codeword. Cryptanalysis intercepted it recently - supposedly something about an experiment in radical bio-modification. I was reminded of it in the aquarium.’ Vargovic fingered the gills in his neck. ‘Something that would make this look like cosmetic surgery. We heard the Demarchy had tailored the sulphur-based metabolism of the ventlings for human use.’

She whistled. ‘That would be quite a trick.’

‘Useful, though - especially if you wanted a workforce who could tolerate the anoxic environments around the vents, where the Demarchy happens to have certain mineralogical interests.’

‘Maybe.’ Cholok paused. ‘But the changes required would be beyond surgery. You’d have to script them in at the developmental level. And even then . . . I’m not sure that what you’d end up with would necessarily be human any more.’ It was as if she shivered, though Vargovic was the one who felt cold, still standing naked beside the revival table. ‘All I can say is, if it happened, no one told me.’

‘I thought I’d ask, that’s all.’

‘Good.’ She brandished a white medical scanner. ‘Now can I run a few more tests? We have to follow procedure.’

Cholok was right: quite apart from the fact that Vargovic’s operation was completely real - and therefore susceptible to complications that had to be looked for and monitored - any deviation from normal practice was undesirable.

After the first hour or so, the real strangeness of his transformation hit home. He had been blithely unaffected by it until then, but when he saw himself in a full-body mirror, in the corner of Cholok’s revival room, he knew that there was no going back.

Not easily, anyway. The Gilgamesh surgeons had promised him they could undo the work - but he didn’t believe them. After all, the Demarchy was ahead of Ganymede in the biosciences, and even Cholok had told him reversals were tricky. He’d accepted the mission in any case: the pay tantalising; the prospect of the sulphur projects rather less so.

Cholok spent most of the day with him, only breaking off to talk to other clients or confer with her team. Breathing exercises occupied most of that time: prolonged periods spent underwater, nulling the brain’s drowning response. Unpleasant, but Vargovic had done worse things in training. They practised fully submerged swimming, using his lungs to regulate buoyancy, followed by instruction about keeping his gill-openings - what Cholok called his opercula - clean, which meant ensuring the health of the colonies of commensal bacteria that thrived in the openings and crawled over the fine secondary flaps of his lamellae. He’d read the brochure: what she’d done was to surgically sculpt his anatomy towards a state somewhere between human and air-breathing fish: incorporating biochemical lessons from lungfish and walking-catfish. Fish breathed water through their mouths and returned it to the sea via their gills, but it was the gills in Vargovic’s neck that served the function of a mouth. His true gills were below his thoracic cavity: crescent-shaped gashes below his ribs.

‘Compared to your body size,’ she said, ‘these gill-openings are never going to give you the respiratory efficiency you’d have if you went in for more dramatic changes—’

‘Like a Denizen?’

‘I told you, I don’t know anything about that.’

‘It doesn’t matter.’ He flattened the gill-flaps down, watching - only slightly nauseated - as they puckered with each exhalation. ‘Are we finished?’

‘Just some final bloodwork,’ she said, ‘to make sure everything’s still functioning properly. Then you can go and swim with the fishes.’

While she was busy at one of her consoles, surrounded by false-colour entoptics of his gullet - he asked her, ‘Do you have the weapon?’

Cholok nodded absently and opened a drawer, fishing out a hand-held medical laser. ‘Not much,’ she said. ‘I disabled the yield-suppresser, but you’d have to aim it at someone’s eyes to do much damage.’

Vargovic hefted the laser, scrutinising the controls in its contoured haft. Then he grabbed Cholok’s head and twisted her around, dousing her face with the laser’s actinic-blue beam. There were two consecutive popping sounds as her eyeballs evaporated.

‘What, like that?’

Conventional scalpels did the rest.

He rinsed off the blood, dressed and left the medical centre alone, travelling kilometres down-city, to where Cadmus-Asterius narrowed to a point. Even though there were many gillies moving freely through the city - they were volunteers, by and large, with full Demarchy rights - he did not linger in public for long. Within a few minutes he was safe inside a warren of collagen-walled service tunnels, frequented only by technicians, servitors or other gill-workers. The late Cholok had been right: breathing air was more difficult now. It felt too thin.

‘Demarchy security advisory,’ said a bleak machine voice emanating from the wall. ‘A murder has occurred in the medical sector. The suspect may be an armed gill-worker. Approach with extreme caution.’

They’d found Cholok. Risky, killing her. But Gilgamesh preferred to burn its bridges, removing the possibility of any sleeper turning traitor after they had fulfilled their usefulness. In the future, Vargovic mulled, they might be better using a toxin, rather than the immediate kill. He made a mental note to insert that in his report.