'I admit,' Case said, 'that I haven't exposed myself to the city's native fragrances for some time now. But you shouldn't knock it. The air isn't quite as filthy as it seems. The purifiers were one of the few things still running after the plague.'

Now that the cable-car had lofted itself past the huddle of buildings which defined her neighbourhood, a much greater expanse of Chasm City was coming slowly into view. It was strange to think that this twisted forest of malformed structures had once been the most prosperous city in human history; the place from which -- for nearly two centuries -- a welter of artistic and scientific innovations had sprung. Now even the locals were admitting that the place had seen better days.

With little in the way of irony they were calling it the City That Never Wakes Up, because so many thousands of its one-time rich were now frozen in cryocrypts, skipping centuries in the hope that this period was only an aberration in the city's fortunes.

Chasm City's border was the natural crater which hemmed the city, sixty kilometres from edge to edge. Within the crater the city was ring-shaped, encircling the central maw of the chasm itself. The city sheltered under eighteen domes which spanned the crater wall and reached inwards to the chasm's rim. Linked at their edges, supported here and there by reinforcing towers, the domes resembled sagging drapery covering the furniture of the recently deceased. In local parlance it was the Mosquito Net, though there were at least a dozen other names, in as many languages. The domes were vital to the city's existence. Yellowstone's atmosphere -- a cold, chaotic mix of nitrogen and methane, spiced with long-chain hydrocarbons -- would have been instantly deadly. Fortunately the crater sheltered the city from the worst of the winds and liquid methane flash-floods, and the broth of hot gases belching from the chasm itself could be cracked for breathable air with relatively cheap and rugged atmospheric processing technology. There were a few other settlements elsewhere on Yellowstone, much smaller than Chasm City, and they all had to go to much more trouble to keep their biospheres running.

Sometimes, in her early days on Yellowstone, Khouri had asked a few of the locals why anyone had ever bothered settling the planet in the first place if it was so inhospitable. Sky's Edge might have its wars, but at least you could live there without domes and atmosphere-cracking systems.

She had quickly learned not to expect anything resembling a consistent answer, if the question itself was not deemed an outsider's impudence. Evidently, though, this much was clear: the chasm had drawn the first explorers and around them had accreted a permanent outpost, and then something like a frontier town. Lunatics, chancers and wild-eyed visionaries had come, driven by vague rumours of riches deep within the chasm. Some had gone home disillusioned. Some had died in the chasm's hot, toxic depths. But a few had elected to stay because something about the nascent city's perilous location actually appealed to them. Fast forward two hundred years and that huddle of structures had become... this.

The city stretched away infinitely in all directions, it seemed, a dense wood of gnarled interlaced buildings gradually lost in murk. The very oldest structures were still more or less intact: boxlike buildings which had retained their shapes during the plague because they had never contained any systems of self-repair or redesign. The modern structures, by contrast, now resembled odd, up- ended pieces of driftwood or wizened old trees in the last stages of rot. Once those skyscrapers had looked linear and symmetrical, until the plague made them grow madly, sprouting bulbous protrusions and tangled, leprous appendages. The buildings were all dead now, frozen into the shapes which seemed calculated to induce disquiet. Slums adhered to their sides, lower levels lost in a scaffolded maze of shanty towns and ramshackle bazaars, aglow with naked fires. Tiny figures were moving in the slums, walking or rickshawing to business along haphazard roadways laid down over old ruins. There were very few powered vehicles, and most of the contraptions Khouri saw looked like they were steam-driven.

The slums never reached more than ten levels up the sides of the buildings before collapsing under their own weight, so for two or three hundred further metres the buildings rose smoothly, relatively unscathed by plague transformations. There was no evidence of occupation in these mid- city levels. It was only near the very tops that human presence again re-asserted itself: tiered structures perched like cranes' nests among the branches of the malformed buildings. These new additions were aglow with conspicuous wealth and power; bright apartment windows and neon advertisements. Searchlights swept down from the eaves, sometimes picking out the tiny forms of other cable-cars, navigating between districts. The cable-cars picked their way through a network of fine branches, lacing the buildings like synaptic threads. The locals had a name for this high-level city-within-a-city: the Canopy.

It was never quite daytime, Khouri had noticed. She could never feel fully awake in this place, not while the city seemed caught in an eternal twilight gloom.

'Case, when are they going to get around to scraping the muck off the Mosquito Net?'

Ng chuckled, a sound like gravel being stirred around in a bucket. 'Never, probably. Unless someone figures a way of making some money out of it.'

'Now who's bad-mouthing the city?'

'We can afford to. When we finish our business we can hightail it back to the carousels with all the other beautiful people.'

'In their boxes. Sorry, Case, count me out of that particular party. The excitement might kill me.'

She could see the chasm now, since the car was skirting close to the sloping inner rim of the toroidal dome. The chasm was a deep gully in the bedrock, weathered sides curving lazily over from horizontal before plunging vertically down, veined by pipes which reached down into belching vapour, towards the atmospheric cracking station which supplied air and heat to the city. 'Talking of which... being killed, I mean -- what's the deal with the weapon?'

'Think you can handle it?'

'You pay me to, I'll handle it. But I'd like to know what I'm dealing with.'

'If you have a problem with that you'd better talk to Taraschi.'

'He specified this thing?'

'In excruciating detail.'

The car was over the Monument to the Eighty now. Khouri had never seen it from this precise angle. In truth, without the grandeur that it attained from street level, it looked weatherworn and sad. It was a tetrahedral pyramid, slatted so that it resembled a stepped temple, its lower levels barnacled in slums and reinforcements. Near the apex the marble cladding gave way to stained- glass windows, but portions of glass were shattered or sheeted-over in metal; damage one never saw from the street. This was to be the venue for the kill, apparently. It was unusual to know that in advance, unless it was another thing that Taraschi had actually had written into his contract.

Contracting to be hunted by a Shadowplay assassin was only usually done if the client thought that they stood a good chance of evading the pursuer over the period determined by the contract. It was the way the virtually immortal rich kept ennui at bay, forcing their behaviour patterns out of predictable ruts -- and ending up with something to brag about when they outlived the contract, as the majority did.

Khouri could date her involvement in Shadowplay very precisely; it was the day she was revived in Yellowstone orbit in a carousel run by an order of Ice Mendicants. Although there had been no Ice Mendicants around Sky's Edge, she had heard stories of them and knew something of their function. They were a voluntary religious organisation who dedicated themselves to assisting those who had suffered some form of trauma while crossing interstellar space, such as the revival amnesia which was a common side-effect of reefersleep.

That in itself was very bad news. Perhaps her amnesia was so bad that it had erased years of her previous life, but Khouri had no recollection even of embarking on an interstellar journey. Her last memories were quite specific, in fact. She had been in a medical tent on the surface of Sky's Edge, lying in a bed next to her husband Fazil. They had both been wounded in a firefight; injuries which -- while not actually life-threatening -- could best be treated in one of the orbital hospitals. An orderly had come around and prepped them both for a short immersion in reefersleep. They would be cooled, carried to orbit in a shuttle, then stacked up in a cryogenic holding facility until surgical slots were available in the hospital. The process might take months, but -- as the orderly smilingly assured them -- there was every chance that the war would still be going on when they were again fit for duty. Khouri and Fazil had trusted the orderly. They were both professional soldiers, after all.

Later, she was revived. But instead of coming around in the recuperation ward in the orbital hospital, Khouri was confronted by Ice Mendicants with Yellowstone accents. No, they explained, she was not amnesiac. Nor had she suffered any kind of injury in the reefersleep process. It was considerably worse than that.

There had been what the lead Mendicant chose to call a clerical error. It had happened around Sky's Edge, after the cryogenic holding facility was hit by a missile. Khouri and Fazil had been among the lucky few not to have been killed by the missile, but the attack had still wiped all the data records in the facility. The locals had done their best to identify the frozen, but inevitably they had made mistakes. In Khouri's case they had confused her with a Demarchist observer who had come to Sky's Edge to study the war and who had been ready to return home to Yellowstone when she was caught in the same missile attack. Khouri had been fast-tracked for surgery and then placed aboard a starship scheduled for immediate departure. They had, unfortunately, not made the same mistake in Fazil's case. While Khouri was asleep, winging her way across the light-years to Epsilon Eridani, Fazil was growing older, one year for every year that she flew. Of course, said the Mendicants, the error was discovered quickly -- but by then it was much too late. There were no other ships due to follow that route for decades. And even if Khouri had immediately returned to Sky's Edge (which was again impossible given the stated destinations of all the ships now parked around Yellowstone), the best part of forty years would have passed before she met Fazil again.

And during most of that time Fazil could have no knowledge that she was coming home; nothing to prevent him picking up the pieces of his life, remarrying, having children and perhaps even grandchildren before she returned, a ghost from a part of his life he might have nearly consigned to oblivion by then. Assuming, of course, that he had not died as soon as he returned to combat.

Until that moment when the Ice Mendicant explained the situation to her, Khouri had never really given much thought to the slowness of light. There was nothing in the universe that moved faster...

but, as she now saw, it was glacial compared to the speed that would be needed to keep their love alive. In one instant of cruel clarity, she understood that it was nothing less than the underlying structure of the universe, its physical laws, which had conspired to bring her to this moment of horror and loss. It would have been so much easier, infinitely easier, if she had known he was dead.

Instead, there was this terrible gulf of separation, as much in time as in space. Her anger had become something sharp inside her, something that needed release if it was not going to kill her from within. Later that day, when the man came to offer her a job as a contract assassin, she found it surprisingly easy to accept.

The man's name was Tanner Mirabel; like her he was an ex-soldier from the Edge. He was a kind of talent scout for potential new assassins. His network taps had flagged her soldiering skills as soon as she was defrosted. Mirabel gave her a business contact: a Mr Ng, a prominent hermetic. An interview with Ng swiftly followed, then a spread of psychometric tests. Assassins, it turned out, had to be among the sanest, most analytic people on the planet. They had to know exactly when a kill would be legal -- and when it would cross the sometimes blurred line into murder and send a company's stocks crashing into the Mulch.

She passed all these tests with ease.

There were other kinds of tests, too. The contractees sometimes specified arcane modes of execution for themselves, while secretly assuring themselves that it would never actually come to that, because they imagined themselves clever and resourceful enough to outrun the assassin, even over weeks or months. But Khouri had to learn an easy familiarity with all manner of weapons, and that turned out to be a talent she had never even suspected in herself.

But she had never seen anything quite like the weapon which the tooth fairy had left.

It had only taken her a minute or so to figure out how the gun's precision parts fitted together.

Assembled, it had the form of a sniper's rifle with a ridiculously fat perforated barrel. The clip contained a number of dartlike slugs: black swordfishes. Near the snout of each slug was a tiny biohazard symbol. It was that holographic death's head which had set her wondering. She had never used toxins against a target before.

And what was this business with the Monument?

'Case,' Khouri said. 'There's one more thing...'

But then the car thumped down on the street, rickshaw drivers peddling furiously to avoid its descent. The toll burst onto her retina. She swiped her little finger through the credit slot, debiting a secure Canopy account which had no traceable links to Omega Point. That was vital, for any well- connected target could have easily traced the movements of their assassin via the ripples they left in the planet's ragged financial systems. Screens and blinds had to be maintained.

Khouri pushed back the gullwing and hopped out. It was, as ever down here, softly raining.

Interior rain, they called it. The smell of the Mulch assailed her instantly, a melange of sewage and sweat, cooking spices, ozone and smoke. The noise was just as inescapable. The constant trundling of rickshaws and the ringing of their bells and horns created a steady clamorous background, spiced with the cries of vendors and caged animals, bursts of song from singers and holograms voicing languages as diverse as Modern Norte and Canasian.

She pulled on a wide-brimmed fedora and closed the raised collar of her kneelength coat. The cable-car rose, grasping high for a dangling cable. It was soon lost among the other specks swinging through the brown depths of the roofed sky.

'Well, Case,' she said. 'It's your show now.'

His voice came through her skull now. 'Trust me. I have a very good feeling about this one.'

The Captain's advice had been excellent, Ilia Volyova thought. Killing Nagorny really had been her only viable option. And Nagorny had made the task that much easier by trying to kill her first, neatly obviating any moral considerations.

All that had happened some months of shiptime ago, and she had delayed attending to the job that now confronted her. But very shortly the ship would arrive around Yellowstone, and the others would emerge from reefersleep. When that happened, her options would be severely limited by the need to maintain the lie that Nagorny had died while sleeping, via some plausible malfunction of his reefersleep casket.

Now she had to steel herself to act. She sat silently in her lab and willed the strength to do what had to be done. Volyova's quarters were not large, by the standards of the Nostalgia for Infinity: she could have allocated herself a mansion of rooms, had she wished. But what would have been the point? Her waking hours were consumed with weapon systems, and little else. When she slept, she dreamed of weapon systems. She allowed herself what few luxuries she had time to use -- enjoy was too strong a term -- and she had sufficient space for her needs. She had a bed and some furniture, utilitarian in design, even though the ship could have outfitted her with any style imaginable. She had a small annex which contained a laboratory, and it was only here that much in the way of attention to detail had been lavished. In the lab, she worked on putative cures for the Captain; modes of attack too speculative to share with the other crew, for fear of raising their hopes.

It was here, also, that she had kept Nagorny's head since killing him.

It was frozen, of course; entombed within a space helmet of old design which had gone into emergency cryopreservation mode the instant it detected that its occupant was no longer living.

Volyova had heard of helmets with razor-sharp irises built into the neck, which quickly and cleanly detached the head from the rest of the body in dire circumstances -- but this had not been one of those.

He had died in an interesting manner, though.

Volyova had woken the Captain and explained the whole Nagorny situation to him: how the Gunnery Officer had appeared to have lost his mind as a consequence of her experiments. She had told the Captain about the problems she had encountered in linking Nagorny into the gunnery systems via the implants she had put in his head. She had even mentioned the fact that Nagorny had been somewhat troubled by recurrent nightmares, before getting quickly to the point that the recruit had attacked her and disappeared into the depths of the ship. The Captain had not drawn her on the subject of the nightmares, and at the time Volyova had been glad of that, for she was not entirely comfortable with discussing them herself, much less analysing their content.

Afterwards, however, she had found it much harder to ignore the subject. The problem lay in the fact that these were not simply random nightmares, however disturbing that might have been. No, from what she could gather, Nagorny's nightmares had been highly repetitious and detailed. For the most part they had concerned an entity called Sun Stealer. Sun Stealer was Nagorny's private tormentor, it seemed. It was not at all clear how Sun Stealer had manifested to Nagorny, but what was beyond doubt was the sense of overwhelming evil the apparition had brought. She had glimpsed something of this in sketches she had found in Nagorny's quarters once: feverish pencil marks limning hideous birdlike creatures, skeletal and empty-socketed. If that was a glimpse into Nagorny's madness, a glimpse was more than adequate. How were these phantasms related to the gunnery sessions? What unsuspected glitch in her neural interface was leaking current into the part of the mind which sparked terrors? With hindsight, it was obvious that she had pushed too hard, too fast. Equally, she had only been following Sajaki's orders to bring the weaponry to a state of full readiness.

So Nagorny had snapped, escaping into the ship's unmonitored warrens. The Captain's recommendation -- that she hunt down and kill the man -- had tallied with her own instincts. But it had taken many days, Volyova deploying webs of sensor gear through as many corridors as she could manage, listening to her rats for any evidence of Nagorny's whereabouts. It had begun to look hopeless. Nagorny would be still at large when the ship arrived in the Yellowstone system and the other crew were woken...

Then, however, Nagorny had made two mistakes: the final flourishes of his madness. The first mistake had been to break into her quarters and leave a message daubed in his own arterial blood on her wall. The message was very simple. She could have guessed in advance the two words Nagorny would choose to leave her.

SUN STEALER.

Afterwards, on the edge of rationality, he had stolen her space helmet, leaving the rest of her suit.

The break-in had drawn Volyova to her cabin, and while she had taken precautions, Nagorny had still managed to ambush her. He had relieved her of the gun she was carrying, and then frogmarched her down a long curving corridor to the nearest elevator shaft. Volyova had tried resisting, but Nagorny's strength was that of the psychotic and his hold on her might as well have been steel. Still, she assumed a chance for escape would present itself as Nagorny took her to wherever he had in mind, once the elevator arrived.

But Nagorny had no intention of waiting for the elevator. With her gun, he forced the door, revealing the echoing depths of the shaft. With nothing in the way of ceremony -- not even a goodbye -- Nagorny pushed Volyova into the hole.

It was a dreadful mistake.

The shaft threaded the ship from top to bottom; she had kilometres to fall before she hit the bottom. And for a few almost heart-stopping moments, she had assumed that was exactly what would happen. She would drop until she hit -- and whether it took a few seconds or the better part of a minute was of no consequence at all. The walls of the shaft were sheer and frictionless; there was no way to gain a purchase or arrest her fall in any way whatsoever.

She was going to die.

Then -- with a detachment which later shocked her -- part of her mind had re-examined the problem. She had seen herself, not falling through the ship, but stationary: floating in absolute rest with respect to the stars. What moved, instead, was the ship: rushing upwards around her. She was not accelerating at all now -- and the only thing that made the ship accelerate was its thrust.

Which she could control from her bracelet.

Volyova had not had time to ponder the details. An idea had formed -- exploded -- in her mind, and she knew that either she executed the idea almost immediately or accepted her fate. She could stop her fall -- her apparent fall -- by ramping the ship's thrust into reverse for however long it took to achieve the desired effect. Nominal thrust was one gee, which was why Nagorny had found it so easy to mistake the ship for something like a very tall building. She had fallen for perhaps ten seconds while her mind processed things. What was it to be, then? Ten second of reverse thrust at one gee? No -- too conservative. She might not have enough shaft to fall through. Better to ramp up to ten gees for a second -- she knew the engines were capable of that. The manoeuvre would not harm the other crew, safely cocooned in reefersleep. It would not harm her, either -- she would just see the rushing walls of the shaft slow down rather violently.

Nagorny, though, was not so well protected.

It had not been easy -- the rush of air had almost drowned out her voice as she screamed the appropriate instructions into the bracelet. Agonising moments had followed before the ship seemed to take any notice of her.

Then -- dutifully -- it had moved to her whim.

Later, she had found Nagorny. The ten gees of thrust, sustained for a second, would not ordinarily have been fatal. Volyova had, however, not whittled her speed down to zero in one go.

She had achieved that through trial and error, and with each impulse Nagorny had been flung between ceiling and floor.

She had been hurt herself; the impacts with the side of the shaft as she fell had broken one leg, but that was healed now and the pain no more than a foggy memory. She remembered using the laser-curette to remove Nagorny's head, knowing that she would need to open it to get at the dedicated implants buried in his brain. They were delicate, those implants, and because they had come into being through laborious processes of mediated molecular growth, she would not be best pleased if they had to be duplicated.

Now it was time to remove them.

She took the head out of the helmet, immersing it in a bath of liquid nitrogen. Then she pushed her hands into two pairs of gauntlets suspended above the workbench within a scaffold of pistons.

Tiny, glistening medical instruments whirred into life and descended on the skull, ready to slice it open in pieces which would later lock back together with fiendish precision. Before reassembling the head, Volyova would insert dummy implants so that -- if the head were ever examined -- it would not seem as if she had removed anything from it. It would have to be re-attached to the body, too -- but there was no need to worry herself too much over that. By the time the others found out what had happened to Nagorny -- what she going to convince them had happened -- they would not be in a hurry to examine him in any kind of detail. Sudjic might be a problem, of course -- she and Nagorny had been lovers, until Nagorny went insane.

Like many others that remained before her, Ilia Volyova would cross that bridge when she came to it.

In the meantime, as she delved deep into Nagorny's head for what was hers, she began to give the first thought to who was going to replace him.

Certainly no one now aboard the ship.

But perhaps around Yellowstone she would find a new recruit.

'Case, are we getting warm?'

The voice came back, blurred and trembly through the mass of the building above her. 'So warm we're incandescent, dear girl. Just hold on and make sure you don't waste those toxin darts.'

'Yes, about those, Case, I----'

Khouri dived aside as three New Komuso trooped past, their heads enveloped in basketlike wicker helmets. Shakuhachi -- bamboo flutes -- cut the air ahead of them like majorettes' staffs, dispersing a gang of capuchin monkeys into the shadows. 'I mean,' she continued, 'what if we take out a collateral?'

'It can't happen,' Ng said. 'The toxin's keyed directly to Taraschi's biochemistry. Hit anyone else on the planet and what they'll have to show for it is a nasty puncture wound.'

'Even if I hit Taraschi's clone?'

'You think you might?'

'Just a question.' It struck her that Case was unusually jumpy.

'Anyway, if Taraschi had a clone, and we killed him by mistake, that would be Taraschi's problem, not ours. It's all in the fine print. You should read it sometime.'

'When I'm gripped by existential boredom,' Khouri said, 'I might try it.'

She stiffened, then, because all of a sudden it was different. Ng was silent, and in place of his voice was a clear pulsing tone. It was soft and evil, like the echolocation pulse of a predator. She had heard that tone a dozen times in the last six months, each time signifying her proximity to the target. It meant that Taraschi was no more than five hundred metres away. That fact, coupled with the onset of the pulse, strongly suggested that he was within the Monument itself.

The moves of the game were now public property. Taraschi would know it, for an identical device -- implanted in a secure Canopy clinic -- was generating similar pulses in his own head.

Across Chasm City, the various media networks which concentrated on Shadowplay would even now be sending their field teams across town to the location of the kill. A lucky few would already be in the vicinity.

The tone hastened as they walked further under the Monument's concourse, but not quickly.

Taraschi must have been overhead -- actually in the Monument -- so that the relative distance between them was not changing swiftly.

The concourse beneath was cracked by land subsidence, lying perilously close to the chasm.

Originally there had been an underground mall complex beneath the structure, but the Mulch had infiltrated it. The lowest levels were flooded, sunken walkways emerging from water the colour of caramel. The tetrahedron of the Monument was elevated well above the concourse and the flooded plaza by a smaller inverted pyramid abutted deep into rock foundations. There was only one entrance to the structure. That meant that Taraschi was as good as dead already, if she caught him aside. But to reach it she had to cross a bridge across the plaza, and her approach would be obvious to the man inside. She wondered what kind of primal thoughts were slipping through his mind now.

In her dreams, she had often found herself in some half-deserted city being chased by some implacable hunter, but Taraschi was experiencing that terror in reality. She remembered that in those dreams the hunter never had to move quickly. That was part of its unpleasantness. She would run desperately, as if through thickened air with weighted-down legs, and the hunter would move with a slowness born of great patience and wisdom.

The pulsing quickened as she crossed the bridge, the ground beneath her feet wet and gritty.

Occasionally the pulsing would slow and requicken, evidence that Taraschi was moving around in the structure. But there was no real escape for him now. He could arrange to be met on the roof of the Monument, perhaps, but in utilising aerial transport he would forfeit the terms of the contract. In the parlours of the Canopy, the shame of that might be less desirable than being killed.