As Saphothere ensconced himself in one of the bunks, Tack drank another glass of whisky and tried to fathom all he had just been told. The whisky didn’t help though, so, after silently toasting Sauros and New London in whatever direction they lay, he headed for one of the bunks himself.

Thadus knew that, in the terms of the people here, he and Elone were untypically old. His hair was grey, yet he did not drool or fall over, and was not dying. Which was why, he supposed, the naked youth up in the oak tree behind them, had not fled and now watched them with fascination. The boy had also probably never seen clothing like this, or the devices they carried, unless in pictures found in the ruins below. Thadus raised his unclipped rifle sight to his eye and scanned the ancient city. He could see one or two cooking fires so some knowledge must survive, despite the fact that everyone here was moronic by the time they reached their twenties and did not live beyond their thirties.

Elone blinked down her nictitating membranes to mirror her eyes. ‘The census figures from the satellite put the population in the region of three thousand.’

‘No sign of anyone developing resistance?’ Thadus asked.

‘None; the opposite, in fact. The population has been dropping steadily over the last thirty years. And what with the new enclave being built a hundred miles north of here…’

Thadus snorted. It was, of course, sensible for those uninfected by the neurovirus, those umbrathants who just by living longer were becoming the rulers of the Umbrathane, to protect themselves from reinfection. He said, ‘I was just wondering if there were any who could be extracted before we cleanse.’ He stabbed his thumb over his shoulder towards the oak tree. ‘The boy there seems pretty well coordinated.’

Elone turned and gazed up into the tree. ‘He’s about twelve years old and malnutrition has delayed his puberty.’

‘Alpha strain, then?’

‘Yes. The hormones produced in puberty trigger the more destructive stage of the virus. Right now only about a quarter of his brain has gone. After another ten years he’ll lose half of what’s remaining, before the virus starts targeting his autonomic nervous system and kills him.’ Elone frowned. ‘But you know all this.’

Thadus turned to her. ‘And I want to hear it again and again. You’re the umbrathant on the ground, and if you’ve any doubts I want to hear them. Do you know how many places like this I’ve cleared out?’

‘You were working on the south coast.’

‘Damned right. Eight old cities all with populations similar to this one, all alpha strain. I know there’s no other answer, but I can still smell burning bodies.’

Thinking about the past, Thadus realized his memories were not so clear as they had been. He checked the monitor inset into the muscle of his forearm and saw that in another five days his mental template would need to be uploaded again to replace memories and abilities lost to the neurovirus he himself carried. By this, and by the cocktail of drugs developed over the last century, he kept the destructive virus at bay. But these only delayed the inevitable and at best two years remained to him. But, then, he was tired and after this last extermination would be unemployed. The rulers in their enclaves would no longer have any use for him and certainly he would not be allowed to live amongst them.

‘What will you use here?’ Elone asked, surreptitiously checking her own monitor.

Thadus tilted his head to the now audible sound of engines. ‘The perimeter’s closing in and any outside the ruins will run for home—that’s what they usually do. We then drop compound B, and do a ground survey while your people collect samples. But we don’t want too many delays. We drop incendiaries before evening.’ He looked beyond her and pointed. ‘There.’

Further along the ridge to their right, overlooking the city, two individuals broke from cover. One was naked, the other wore rotting skins and carried a primitive spear. They bolted down the slope into low scrub before the buildings. Behind them a tree went over with a rushing crash and an armoured car emerged from the forest. All this activity became too much for the boy in the oak tree behind Thadus and Elone, and he scrambled to the ground. In one smooth motion Thadus clipped the sight back onto his rifle, aimed and acquired the boy as he scrambled past. Thadus then lowered the rifle.

‘See?’ he said. ‘They run for home.’

In an unconscious gesture, he now pressed a finger to the comlink in his ear. ‘Dolure had to flame out a cave some were hiding in, but otherwise that’s all of them. The bomber’s on its way over.’

Both he and Elone detached masks from their belts and donned them. All around the ancient city troops and Elone’s monitoring personnel were walking out of the surrounding forest, and other armoured cars were now driving into view. Then came a different engine sound as high up the tricopter bomber droned overhead and took up station above the city. There it shed its load like a sprinkling of black peppercorns. With his rifle sight back up against his eye, Thadus watched the gaseous detonations and the haze of compound B spreading between the buildings.

He checked his watch, gave it ten minutes. ‘Let’s walk,’ he said.

And as he and Elone did that, the Umbrathane perimeter also closed in on the city. It was only minutes later that they started seeing victims of the poison gas: family groups gathered around fires, some clothed in animal skins, others so far gone in cerebral breakdown that they had been unable even to maintain this primitive clothing; individuals who had run and been felled by the gas; older victims of the plague curled up in stinking cavities in the fallen masonry, where they had survived only if their kin remembered to feed them; others rotting in those same cavities. While Thadus walked with his rifle propped across his forearm, Elone went to rejoin her people—infected umbrathants like himself and his men—who were now spreading out to take tissue and blood samples. His own men checked for anyone alive, but in a desultory manner—Thadus had never found a survivor of the gas in all the cities he had cleansed.

Then he saw the boy.

For a moment Thadus thought he was seeing some ape that lived in the ruins with the people. Often there had been troops of macaques, chimpanzees and baboons—escaped from zoos and living wild for centuries now. But compound B was tailored to kill them as well, as they also carried the neurovirus. He gave chase to the figure darting amongst the ruins, realizing he was seeing the boy who had earlier hidden in the oak tree. How was it he was still alive? Thadus needed to bring this boy to Elone for study. He grimaced to himself, remembering his rifle had already acquired this youth. Elone did not need the boy to be alive for her tests. Finally getting a clear view, Thadus halted and raised his rifle to his shoulder.

‘Thadus, the tricopter is coming back,’ Elone told him over com.

Thadus hesitated. The ‘copter wasn’t due back until the evening. Then, just about to fire, he saw two of his men round a crumbling vine-cloaked pillar ahead of the boy.

‘Grab him!’ he shouted. And that shout seemed to unleash nightmares.

Thadus looked up and saw the tricopter looming over the ruins, its bay doors opening. There was no confusion in him about that. Here was a neat solution for the enclave dwellers: exterminate inconveniences like himself, Elone, and their people, along with the last of the feral humans. But then he looked ahead and saw that behind the two men the air shimmered and distorted as a line of heat haze cut it vertically. Then that cut began to evert, exposing something monstrous.

‘What the hell?’

Screams were now coming over com, not from the two who were after the boy, for they had yet to see the horror looming behind them, nor from his fellows who had seen the ‘copter — Thadus knew they would not scream at that. He scanned to his right and saw a terrifying vertical mouth, three metres high, its inside turning like toothed conveyers, hoovering up corpses and running umbrathants, sucking the living and the dead into a meat pulverizer. More screams. To his left a similar mouth being propelled down a street by a huge tentacle, slamming shut on four umbrathants, then withdrawing to snap up at its leisure the scattered corpses of feral humans. All around, death. Above, incendiary cylinders tumbling down through the sky from the tricopter. Ahead his two men, torn apart and turned away into an organic hell, which then closed out of existence.