Cryobiology was actually a venerable industry.

The key to its utility was that far below the freezing point of water, molecules slowed the frenetic pace that permitted chemical reactions to proceed. So red blood cells could be stored for a decade or more. You could freeze, thaw, and reuse corneas, organ tissue, neural tissue. You could even freeze embryos. The cold was as much an enemy as an ally, of course; expanding crystals of ice had an unpleasant habit of destroying cell walls. So the medicos infused tissues with cryoprotective agents like glycerol and dimethyl sulfoxide.

Still, freezing and reviving a complex mature organism- such as a hundred kilograms of blasphemous Royal Navy pilot- presented more of a challenge. In Snowy's body there were many different types of cells, each requiring a different freeze-thaw profile. In the end, a little subtle genetic engineering had done the trick. Snowy's cells had been given the ability to manufacture natural antifreeze- in fact, glycoproteins, a trick borrowed from some species of polar fish- and the freezing was regulated at the level of the cells themselves.

Obviously it had worked. Snowy had come out of the process alive and functioning. After half an hour he barely felt a thing.

Of course he had been intended to come out fighting.

Officially this unit was under the command of UNPROFOR, the UN Protection Force. But everybody knew that was only a cover. The strategy had become known as sowing dragon's teeth. sowing dragon's teeth. As the intensity of global conflict had rapidly increased, post-Rabaul, new forms of deterrence had been devised. The idea was that it would be futile for any power to attempt an invasion if it knew that the ground was salted with groups of highly trained military personnel, fresh and fully equipped, ready to resume the battle. From these scattered teeth the dragon would regrow. That was the theory. As the intensity of global conflict had rapidly increased, post-Rabaul, new forms of deterrence had been devised. The idea was that it would be futile for any power to attempt an invasion if it knew that the ground was salted with groups of highly trained military personnel, fresh and fully equipped, ready to resume the battle. From these scattered teeth the dragon would regrow. That was the theory.

There were drawbacks, of course. The cold sleep process itself brought a risk of injury or fatality (but low, not 75 percent 75 percent). And you never knew where you would be stationed; the freezing had been done at huge central depots, the subjects transported and deposited, all unconscious, at selected sites around the country, even abroad. But Snowy had known that his unit of Navy flyers would be kept together, which was more than reassuring.

And there were worse assignments. The tour of duty was limited to two years. For sure it was safer than being posted on a carrier to one of the world's oceanic hellholes, the Adriatic or the Baltic or the South China Sea. In all, it was odd but it was just another posting.

Snowy had been happy to go along with it, even though it meant being locked away from his wife. He had expected to come out of the hole healthy and happy, a lot richer with the back pay he hadn't been able to spend. Or, failing that, the grimmer possibility would be that he would have to come out fighting. But that was what he was trained for. Even then, he had expected to emerge into the middle of an ongoing high-tech war, to find a chain of command, everything basically functioning, to find something to fly. fly. That was why they had salted away pilots in the first place. He hadn't expected that they would be cracking the door cut off from any chain of command, completely ignorant of conditions outside- ignorant even of where he That was why they had salted away pilots in the first place. He hadn't expected that they would be cracking the door cut off from any chain of command, completely ignorant of conditions outside- ignorant even of where he was. was. But that was what he faced. But that was what he faced.

Snowy took the lead. He stepped through the hatch.

Beyond the hatch, a stairwell was cut into concrete. The well led up to a rectangle of bright green light: leaves, traces of blue-white sky beyond. A forest?

The stairwell's concrete, where it was exposed, was stained brown where metal fittings had rusted away. And when Snowy put his weight too close to the edge of a step, the concrete just crumbled. The stairs themselves were barely visible under a tangle of moss, leaves, debris of all kinds. Snowy wasted a little energy trying to clear this stuff off, but found that much of it was actually growing here, out of a layer of mulch over the concrete.

Ignoring the mess, he stepped up and just pushed his way out of the well.

At last he found himself standing on leaf-covered ground. He was panting hard. Evidently the cold sleep had taken more out of him than he had expected. The others followed him, one by one, brushing dead leaves and moss and mulch off their clothes.

The forest was built of tall trees, with low branches, heavy, spreading leaves. Oak, perhaps. Wind rustled, bringing warm air to Snowy's face. It felt like late spring or early summer. The air smelled fresh, of nothing but forest, green and mulchy.

The Pit was set in the ground, half-concealed by a great concrete lid. But the lid was tilted askew and cracked, and plants were growing out of its surface.

Ahmed had a small black backpack. This contained a clockwork radio transceiver- which, like the pistols, had been stored in oil. Now he turned this on, wound it up, extended its aerial and began to walk around the little clearing.

Both Moon and Bonner looked very young and scared, lost in the green shade.

Sidewise stood by Snowy. Moodily he kicked the concrete carapace. "It's amazing the power supply kept going as long as it did."

Snowy said, "It's like we just clambered out of Chernobyl."

"I don't think Chernobyl is a problem anymore."

"What?"

"Snow, just how long do you think we've been stuck down that hole?"

Snowy braced himself. "More than fifty years?"

Sidewise grunted. "Look around you, pal. Those trees are oak. oak. And look at this." He led Snowy to a fallen tree. The trunk had snapped off maybe a meter above the ground. Much of the fallen trunk was coated with greenery, and fat, platelike fungi adhered to the upright stub of trunk, like disks stuck into the wood. "Snow," said Sidewise, "you are surrounded by a mature forest. These are And look at this." He led Snowy to a fallen tree. The trunk had snapped off maybe a meter above the ground. Much of the fallen trunk was coated with greenery, and fat, platelike fungi adhered to the upright stub of trunk, like disks stuck into the wood. "Snow," said Sidewise, "you are surrounded by a mature forest. These are old old trees. This one got so old it died without being felled. Come on, Snow. You remember those eco classes in training. What happens if you let a forest clearing recover?" trees. This one got so old it died without being felled. Come on, Snow. You remember those eco classes in training. What happens if you let a forest clearing recover?"

The grasses and herbs would be first to colonize the empty space. Within a year or so there would be Scots pine seedlings, birches, other deciduous trees sprouting from seeds left in the ground, or from stumps. Once there was some protection from the frost, Norway spruce and chestnut might take hold. Then, as conditions changed, different species would compete for light and space. After maybe fifty years, as the recovering forest darkened, the grasses on the floor would make way for shade-tolerant vegetation like bilberry and mosses. And after that, that, the oaks would return. the oaks would return.

Snowy hadn't paid a great deal of attention to this kind of stuff, at school, during his training, or later. Eco was always too depressing, nothing but lists of dead creatures. But- how long? how long?

Sidewise poked at the grounded trunk. "Look at these bryophytes- the mosses and liverworts- and the lichens, fungi, insects burrowing away. You know, in our day a sight like this dead trunk was as rare as a wolf."

"In our day?"

Ahmed had given up his stroll around the clearing. "Nothing," he said. "Not a peep on any frequency. Not even GPS."

"Maybe the radio's out," Moon said.

Ahmed pressed a green button on the set. "The self-test is okay."

"Then," said Bonner, "what do we do?"

Ahmed straightened up. "We keep ourselves alive. We get out of this damn forest. And we find somebody to report to."

Snowy nodded. "Which way?"

"The maps," said Bonner immediately.

Their training asserted itself, and they hurried back to the Pit.

The Pit had been equipped with external stores of paper maps, in case of the eventuality that a troop found itself revived like this without external direction or orientation. The maps were supposed to be contained in weatherproof boxes on the exterior of the Pit. The maps would also come with spins- specific instructions. Snowy knew they would all be reassured to find something to tell them what to do, maybe a clue as to what was going on.

But, try as they might, they couldn't even find a trace of the map boxes. There was nothing but a surface of corroded, crumbling concrete, heavily colonized by mosses and grass.

Sidewise helped with the search, but Snowy could tell that his heart wasn't in it. He had known known the maps wouldn't be here. Snowy began to feel vaguely scared of Sidewise, because he was so far ahead of the game; he really didn't want to know what Sidewise had already figured out. the maps wouldn't be here. Snowy began to feel vaguely scared of Sidewise, because he was so far ahead of the game; he really didn't want to know what Sidewise had already figured out.

They gave up on the maps. Still Ahmed tried to take a lead, to be decisive, and Snowy admired him for that. Ahmed sniffed the air, looked around, and pointed. "The land is rising that way. So that's the way we'll go. If we're lucky, we'll break out of these woods. Agreed?"

He was rewarded by shrugs and nods.

II.

There wasn't much to take from the Pit- nothing but what they could plunder from the dead: all the weapons and ammo they could find, spare clothing, ration packs. They made backpacks from spare flight suits, and loaded up their gear.

They set off in the direction Ahmed had chosen. The sun looked to be setting, and that meant, Snowy thought, that they had to be traveling roughly north. Unless even that that had gotten itself screwed up in the years they had lost in the Pit. had gotten itself screwed up in the years they had lost in the Pit.

The forest was dominated by the great oaks, though they were interspersed with other species like sycamore, Norway maple, and conifers. There were plenty of birds- mostly starlings, it seemed to Snowy- but he was startled to see a rattle of green and yellow wings pass across the sun. Occasionally they saw animals- rabbits, squirrels, small, timid-looking deer, even what looked like a wolf, which had them all fingering their pistols.

After maybe an hour they came to a neat round hole in the ground. It was full of debris, but was obviously man-made. The bit of human design drew them insistently. They gathered around, sipping water from the small vials they carried.

Snowy said to Sidewise, "Did you see those green birds? They looked like-"

"Budgerigars. The descendants of escaped pets. Why not? There are probably parakeets and parrots too. Some of those deer looked like muntjac to me. Out of zoo stock, maybe. Even some of the trees look like imports- like that turkey oak back there. Like they taught us: Once you disturb the balance of nature, once you start importing species, it never goes back the way it used to be."

Snowy said, "There was a wolf."

"You sure it was a wolf?" Sidewise said sharply. "Didn't it look too low, too fast?"

Come to think of it, Sidewise was right. It had looked a little furtive, low-slung. Rodentlike.

Bonner said, "All right, two-brains, what about this hole in the ground? Somebody's removed a tree stump here, and done it deliberately."

"Maybe," said Sidewise coldly. "But holes in the ground last a long time. You can still find holes dug by hunter-gatherers tens of thousands of years ago. All this tells us is there hasn't been another Ice Age yet."

Ahmed glared at him. "You aren't doing much for morale, Sidewise."

Sidewise shot back, "And what about my morale? It does me no damn good to ignore what's blindingly obvious all around us."

There was a moment of strained silence. For a minute Snowy glimpsed Sidewise's past, a past he never talked about: the too-brainy kid at school, impatient of the rest, constantly bullied back into line by his fellows.

"Let's move on," Bonner said gruffly. Ahmed nodded and led the way.

Soon they came to what looked like a track. It was nothing but a winding ribbon of earth, almost invisible, crooked and devious. But the vegetation here grew a little sparser, and Snowy could feel how the ground did not give under his feet as it did elsewhere. A track, then- and surely a human-made track, not animal, if the ground had been compacted as much as it felt.

They didn't say anything. Nobody wanted this little bit of hope to be punctured by another lecture from Sidewise. But they all followed the track, walking single file, moving that much more briskly up the shallow slope.

Snowy already felt exhausted, strung out.

He found he wasn't thinking of his wife, his buddies back home, the life that seemed to have vanished forever. Everything was too strange for that. But he longed, absurdly, for the snug safety of his cold-sleep bed, with its enclosing carapace and humming machines. Out here he felt very exposed- his PPK didn't add up to much protection- and he was very aware that when darkness fell in this strange, transformed place they were going to be very vulnerable.

We have to find some answers before then, he thought.

After maybe another hour the trees thinned out, and with relief Snowy found himself walking out in the open. But he still couldn't see much. He was on the breast of a broad shallow rise, its summit hidden over the nearby horizon. The ground was chalky, he saw, and the soil thin and heavily eroded. Nothing much grew here but heather, and shoulders of bare rock stuck out of the ground.

The sky was clear, save for a scattering of thin, high cloud. The setting sun cast long shadows on the ground. It was so low that Snowy would have expected the sunset to have started already, a tall Rabaul-ash light show. But there was no redness in the western sky; the sun shone bright and white. Was the ash gone?

Moon yelped. "Tracks! Vehicle tracks!" She was pointing a little way down the slope to their right, jumping up and down with excitement.

They all ran that way, their improvised packs bouncing on their backs.

She was right. The tracks were quite unmistakable. They had been made by some off-road vehicle, and they ran at an angle down the slope.

The mood was suddenly exultant. Bonner was grinning. "So there's somebody around. Thank Christ for that."

"All right," Ahmed said. "We have a choice. We can keep on heading for the high ground, looking for a viewpoint. Or we can follow these tracks back downhill and find a road."

The high ground would probably have been the smarter move, Snowy thought. But in the circumstances none of them wanted to let go of these traces of human activity. So they started downhill, following the twin scars in the hillside.

Sidewise walked beside Snowy. "This is dickheaded," he muttered.

"Side-"

"Look at it. These are vehicle tracks, all right. But they have turned into gullies. Look over there. They've eroded right down to the bedrock. Snow, in an area like this, above the treeline, it can take centuries for a covering of soil and vegetation to re-establish itself once it's removed. Centuries. Centuries."

Snowy stared at him. His thin face was gray in the fading light. "These tracks look like they were made yesterday, as if somebody just drove by."

"I'm telling you they could be any age. I don't fucking know. know." He looked as if he was dying for a cigarette.

The tracks wound down the hillside, eventually leading them into a broad valley that cupped the silvery streak of a river. The tracks veered off the rough ground onto what was unmistakably a road following the valley wall, a neat flat shelf carved almost parallel to the valley's contours.

The group clambered into the road surface with relief. They started to hike down the road, along the valley toward the lower ground, their mood staying high despite their fatigue.

But the road was in bad shape, Snowy saw. It was overgrown. There was still some asphalt- he could see it as black fragments in the green- but it had aged, becoming cracked and brittle. Plants and fungi had long since broken through the surface, and in fact as he walked he sometimes had to push through thickets of birch and aspen seedlings. It was less like walking along a road than over a sparsely vegetated ridge.

Sidewise was walking alongside him again. "So what do you think? Where are we?"

They had all been trained up in the basic geographical features of Europe and North America. "The valley isn't glaciated," Snowy said reluctantly. "So if we're in Europe, we aren't too far north. Southern England. France maybe."

"But it's been a long time since anybody maintained this road. And look down there." Sidewise pointed to a line etched in the side of the far valley wall, just bare rock.

"So what?"

"See how level it is? I think this valley was flooded once. Dammed. At the water's surface you get a lot of erosion- you get horizontal cuts like that- because when the flow is managed, the water levels fluctuate fast."

"So where's the dam?"

"We'll come to it," said Sidewise grimly.

After another hour of walking, they did.

They turned around a breast of the valley, and there it was. A branch of this roadway actually led down to the dam, and must have run over it to the valley's far side.

But the dam was gone. Snowy could make out the piers that still clung to the shore, heavily eroded and overgrown with greenery. Of the central section, the great curving wall and gates and machinery that had once tamed the river, there was nothing left but a hummocky arced line on the valley floor, a kind of weir that barely perturbed the river as it ran over it.

Moon said, "Maybe somebody blew it up."

Sidewise shook his head. "Nothing is impervious. There are always cracks and weaknesses, places the water can get into. And if you don't do anything about it, the leaks get worse, until..." He fell silent. "All you need is time," he finished lamely.

"Fucking hell," growled Bonner. "Fucking buggering hell."

It seemed to Snowy that the unavoidable truth was starting to sink into them all. Even Sidewise didn't need to say any more to make it so.

Ahmed strode ahead a few paces, and peered further down the valley. He was a pilot; like them all, he had good eyes. He pointed. "I think there's a town down there."

Maybe, thought Snowy. It was just a splash of greenish gray. He could see no movement, no car windshields or windows glinting, no smoke rising, no lights. But they had nowhere else to go.

Before they left the higher ground Ahmed fired off a couple of the search-and-rescue flares he had retrieved from the shelter. There was no reply.

They followed Ahmed as he made bold, defiant strides along the grassed-over roadway, down the valley toward the town. The light began to fade. Not a single light came on in the town they approached; it was a well of darkness and silence.

In some places the river's banks had reverted to marsh, with low, green-clad hummocks marking what might once have been buildings. Elsewhere the banks were lined with elder and graceful willows- old old-looking willows, Snowy thought reluctantly- and the floodplain beyond was covered by a forest of poplar and ash. Beyond, he could see arms of the oak forest spreading over the low hills.

Long before they reached the center of the town they had to abandon the grown-over road, as it slipped under the surface of the broadening river. Further out into the river, Snowy could make out shapes, lines, under the shallow water.