A hundred and fifty generations deep, and the bronze tools gave way, at last, to stone. But the stone-worked fields were little changed. As the pace of historical change slowed, David let them fall faster. Two hundred, three hundred generations passed, the fleeing faces blurring one into the other, slowly molded by time and toil and the mixing of genes.

  But soon it will mean nothing, David thought bleakly—nothing, after Wormwood Day. On that dark morning all of this patient struggle, the toil of billions of small lives, will be obliterated; all we have learned and built will be lost, and there may not even be minds to remember, to mourn. And time's wall was close, much closer even than the Roman spring they had glimpsed; so little history might be left to play itself out.

  Suddenly it was an unbearable thought, as if he had imaginatively absorbed the reality of the Wormwood for the first time. We must find a way to push it aside, he thought. For the sake of these others, the old ones who stare out at us through the WormCam. We must not lose the meaning of their vanished lives.

  And then, suddenly, the background was a blur once more.

  Bobby said, "We've become nomads. Where are we?"

  David tapped a reference panel. "Northern Europe. We forgot how to do agriculture. The towns and settlements have dispersed. No more empires, no cities. Humans are pretty rare beasts, and we live in nomadic groups and clans, settlements that last a season or two at best."

  Twelve thousand years deep, he paused the scan.

  She might have been fifteen years old, and there was a round sigil of some kind crudely tattooed onto her left cheek. She looked in rude health. She carried a baby, swaddled in animal hide—my remote great-uncle, David thought absently—and she was stroking its round cheek. She wore shoes, leggings, a heavy cloak of plaited grasses. Her other garments seemed to have been stitched together from strips of skin. There was grass stuffed into her shoes and under her hat, presumably for insulation.

  Cradling her baby, she was walking after a group of others: men, women with infants, children. They were making their way up a shallow, sloping ridge of rock. They were walking casually, easily, a pace that seemed destined to carry them many kilometers. But some of the adults had flint-tipped spears at the ready: presumably as a guard against animal attack rather than any human threat.

  She topped the ridge. David and Bobby, riding at their grandmother's shoulder, looked with her over the land beyond.

  "Oh, my," David said. "Oh, my."

  They were looking down over a broad, sweeping plain. In the far distance, perhaps the north, there were mountains, dark and brooding, striped with the glaring white of glaciers. The sky was crystal blue, the sun high.

  There was no smoke, no tracery of fields, no fencing. All the marks made by humans had been erased from his chill world.

  But the valley was not empty.

  ...It was like a carpet, thought David: a moving carpet of boulder-like bodies, each coated in long red-brown fur that dangled to the ground, like the fur of a musk ox. They moved slowly, feeding all the while, the greater herd made up of scattered groups. At the near fringe of the herd, one of the young broke away from its parent, incautiously, and began to paw at the ground. A wolf, gaunt, white-furred, crept forward. The calf's mother broke from the pack, curved tusks flashing. The wolf fled.

  "Mammoth," David said.

  "There must be tens of thousands of them. And what are they, some kind of deer? Are those camels? And—oh, my God—I think it's a saber-toothed cat."

  "Lions and tigers and bears," David said. "Do you want to go on?"

  "Yes. Yes, let's go on."

  The Ice Age valley disappeared, as if into mist, and only the human faces remained, falling away like the leaves of a calendar.

  Still David felt he could recognize the faces of his ancestors: round, almost always devastatingly young when giving birth, and still retaining that signature of blue eyes and strawberry-blond hair.

  But the world had changed dramatically.

  Great storms battered the sky, some lasting years. The ancestors struggled across landscapes of ice or drought, even desert, starving, thirsty, never healthy.

  "We've been lucky," David said. "We've had millennia of comparative climate stability. Time enough to figure out agriculture and build our cities and conquer the world. Before that, this."

  "So very fragile," Bobby said, wondering.

  More than a thousand generations deep, the faces began to grow darker.

  "We're migrating south," Bobby said. "Losing our adaptation to the colder climates. Are we going back to Africa?"

  "Yes." David smiled. "We're going home."

  And in a dozen more generations, as this first great migration was undone, the images began to stabilize.

  This was the southern tip of Africa, east of the Cape of Good Hope. The ancestral group had reached a cave, close to a beach from which thick, tan sedimentary rocks protruded.

  It seemed a generous place. Grassland and forest, dominated by bushes and trees with huge, colorful, thistly flowers, lapped right down to the sea's edge. The ocean was calm, and seabirds wheeled overhead. The inter-tidal shoreline was rich with kelp, jellyfish and stranded cuttlefish.

  There was game in the forest. At first they glimpsed familiar creatures like eland, springbok, elephant and wild pig, but deeper in time there were more unfamiliar species; long-horned buffalo, giant hartebeest, a kind of giant horse, striped like a zebra.

  And here, in these unremarkable caves, the ancestors stayed, generation on generation.

  The pace of change was now terribly slow. At first the ancestors wore clothes, but—as hundreds of generations withered away—the clothing was of decreasing quality, reducing at last to simple skin bags tied around naked waists, and at length not even that. They would hunt with stone-tipped spears and hand axes, no longer with arrows. But the stone tools too were of increasing coarseness, the hunting less ambitious, often no more than a patchy attempt to finish off a wounded eland.

  In the caves—whose floors gradually sank deeper over the millennia, as successive layers of human detritus were removed—at first there was something like the sophistication of a human society. There was even art, images of animals and people, laboriously layered on the walls with dye-stained fingers.

  But at last, more than twelve hundred generations deep, the walls became blank, the last crude images scraped away.

  David shivered. He had reached a world without art: there were no pictures, no novels, no sculptures, perhaps not even songs or poetry. The world was draining of mind.

  Deeper and deeper they fell, through three, four thousand generations: an immense desert of time, crossed by a chain of ancestors who bred and squabbled in this unadorned cave. The succession of grandmothers showed little meaningful change—but David thought he detected an increasing vagueness, a bewilderment, even a state of habitual, uncomprehending fear in those dark faces.

  At last there was a sudden, jarring discontinuity. And this time it was not the landscape that changed but the ancestral face itself.

  David slowed the fall, and the brothers stared at this most remote grandmother, peering from the mouth of the African cave her descendants would inhabit for thousands of generations.

  Her face was outsized, with her eyes too far apart, nose flattened, and features spread too wide, as if the whole face had been pulled wide. Her jaw was thick, but her chin was shallow and sliced back. And bulging out of her forehead was an immense brow, a bony swelling like a tumor, pushing down the face beneath it and making the eyes sunken in their huge hard-boned sockets. A swelling at the back of her head offset the weight of that huge brow, but it tilted her head downward, so that her chin almost rested on her chest, her massive neck snaking forward.

  But her eyes were clear and knowing.

  She was more human than any ape, and yet she was not human. And it was that degree of closeness yet difference which disturbed him.

  She was, unmistakably, Neanderthal.

  "She's
beautiful," Bobby said.

  "Yes," David breathed. "This is going to send the paleontologists back to the drawing board." He smiled, relishing the idea.

  And, he wondered suddenly, how many watchers from his own far future would be studying him and his brother, even now, as they became the first humans to confront their own deep ancestors? He supposed he could never begin to imagine their forms, the tools they used, their thoughts—even as this Neanderthal grandmother could surely never have envisaged this lab, his half-invisible brother, the gleaming gadgets here.

  And beyond those watchers, still further into the future, there must be others watching them in turn—and on, off into the still more unimaginable future, as long as humanity—or those who followed humans—persisted. It was a chilling, crushing thought.

  All of it—supposing the Wormwood spared anybody at all.

  "...Oh," Bobby whispered. He sounded disappointed.

  "What is it?"

  "It's not your fault. I knew the risk." There was a rustle of cloth, a blurred shadow.

  David turned. Bobby had gone.

  But here was Hiram, storming into the lab, clattering doors and yelling. "I got them. Bugger me, I got them." He slapped David on the back. "That DNA trace worked like a charm. Manzoni and Mary, the pair of them." He raised his head. "You hear me, Bobby? I know you're here. I got them. And if you want to see either of them again, you have to come to me. You got that?"

  David stared into the deep eyes of his lost ancestor—a member of a different species, five thousand generations removed from himself—and cleared down the SoftScreen.

  Chapter 27—FAMILY HISTORY

  When she was forcibly restored to open human society, Kate was relieved to find she'd been cleared of the criminal conviction brought against her. But she was stunned to find she was taken away from Mary, her friends, and immediately incarcerated—by Hiram Patterson.

  The door to the suite opened, as it did twice a day.

  There stood her guard; a woman, tall, willowy, dressed in a sober businesslike trouser suit. She was even beautiful—but with a deadness of expression and in her dark eyes that Kate found chilling.

  Her name, Kate had learned, was Mac Wilson.

  Wilson pushed a small trolley through the door, hauled out yesterday's, cast a fast, professional glance around the room, then shut the door. And that was that, over without a word.

  Kate had been sitting on the room's sole piece of furniture, a bed. Now she got up and crossed to the trolley, pulled back its white paper cover. There was cold meat, salad, bread, fruit, and drinks, a flask of coffee, bottled water, orange juice. On a lower deck there was laundry, fresh underwear, jumpsuits, sheets for Kate's bed. The usual stuff.

  Kate had long exhausted the possibilities of the twice-daily trolley. The paper plates and plastic cutlery were useless for anything but their primary purpose, and a nearly useless for that. Even the wheels of the trolley were of soft plastic. She went back to her bed and sat desultorily munching on a peach.

  The rest of the room was just as unpromising. The walls were seamless, coated with a clear plastic she couldn't dig her nails through. There wasn't even a light fitting; the gray glow that flooded the room—twenty-four hours a day—came from fluorescents behind ceiling panels, sealed off behind plastic, and anyhow out of her reach. The bed was a plastic box seamlessly attached to the floor. She'd tried ripping the sheets, but the fabric was too tough. (And anyhow she wasn't yet ready to visualize herself garrotting anybody, even Wilson.)

  The plumbing, a john and a shower fixture, was likewise of no value to her greater purpose. The toilet was chemical, and it seemed to lead to a sealed tank, so she couldn't even smuggle out a message in her bodily waste—even supposing she could figure out how.

  ...But despite all that, she had come close to escape, once. It was enjoyable to replay her near-triumph in her mind.

  She'd concocted the scheme in her head, where even the WormCam couldn't yet peer. She'd worked on her preparations for over a week. Every twelve hours she had left the food trolley in a slightly different place—just that fraction further inside the room. She choreographed each setup in her head: three paces from bed to door, cut the second pace by that fraction more...

  And each time she'd come to the door to collect the trolley, Wilson had been forced to reach a little further.

  Until at last there came a time when Wilson, to reach the trolley, had to take a single pace into the room. Just a pace, that was all—but Kate hoped it would be enough.

  Two running steps took her to the doorway. A shoulder charge knocked Wilson forward into the room, and Kate made it as far as two paces out the door.

  Her room turned out to be just a box, standing alone in a giant, hangar-sized chamber, the walls high and remote and dimly lit. There were other guards all around her, men and women, getting up from desks, drawing weapons. Kate looked around frantically, seeking a place to run—

  The hand that had closed on hers was like a vise. Her little finger was twisted back, and her arm bent sideways. Kate fell to her knees, unable to keep from screaming, and she felt bones in her finger break in an explosion of grinding pain.

  It was, of course, Wilson.

  When she'd come to, she was on the floor of her prison, bound there with what felt like duct tape, while a medic treated her hand. Wilson was being held back by another of the guards, with a murderous look on that steely face.

  When it was done, Kate had a finger that throbbed for weeks. And Wilson, when she next came to the door on her twice-daily routine, fixed Kate with a glare full of hate. I wounded her pride, Kate realized. Next time, she will kill me without hesitation.

  But it was clear to Kate that, even after her attempted escape, all that hate wasn't directed at her. She wondered who was Wilson's real target—and if Hiram knew.

  In the same way, she knew, she had never been Hiram's real target. She was just bait, bait in a trap.

  She was just in the way of these crazy people with their unguessable agendas.

  It did no good to brood on such things. She lay back on her bed. Later, in the routine she'd used to structure her empty days, she'd take some exercise. For now, suspended in light that was never quenched, she tried to blank her mind.

  A hand touched hers.

  Amid the chaos and recrimination and anger that followed the retrieval of Mary and Kate, David asked to see Mary in the cool calm of the Wormworks.

  He was immediately jotted by the familiarity of Mary's blue eyes, so like the eyes he had followed deep into time, all the way back to Africa.

  He shivered with a sense of the evanescence of human life. Was Mary really no more than the transient manifestation of genes which had been passed to her through thousands of generations, even from the long-gone Neanderthal days, genes which she in turn would pass on into an unknown future? But the WormCam had destroyed that dismal perspective. Mary's life was transient, but no less meaningful for that; and now that the past was opened up, she would surely be remembered, cherished by those who would follow.

  And her life, shaped in a fast-changing world, might yet take her to places he couldn't even imagine.

  She said, "You look worried!"

  "That's because I'm not sure who I'm speaking to."

  She snorted, and for an instant he saw the old, rebellious, discontented Mary.

  "Forgive my ignorance," David said. "I'm just trying to understand. We all are. This is something new to us."

  She nodded. "And therefore something to fear?... Yes," she said eventually. "Yes, then. We're here. The wormhole in my head never shuts down, David. Everything I do, everything I see and hear and feel, everything I think, is."

  "Shared?"

  "Yes." She studied him. "But I know what you imply by that. Diluted. Right? But it isn't like that. I'm no less me. But I am enhanced. It's just another layer of mind. Or of information processing, if you like: layered over my central nervous system, the way the CNS is layered over older networks, like the
biochemical. My memories are still mine. Does it matter if they are stored in somebody else's head?"

  "But this isn't just some kind of neat mobile phone network, is it? You Joined make higher claims than that. Is there a new person in all this, a new, combined you. A group mind, linked by wormholes, emergent from the network?"

  "You think that would be a monstrosity, don't you?"

  "I don't know what to think about it."

  He studied her, trying to grasp Mary within the shell of Joinedness.

  It didn't help that the Joined had quickly become renowned as consummate actors—or liars, to be more blunt. Thanks to their detached layers of consciousness, each of them had a mastery over their body language, the muscles of their faces—a power over communication channels that had evolved to transmit information reliably and honestly—that could beat out the most expert thespian. He had no reason to suppose Mary was lying to him, today; it was just that he couldn't see how he could tell if she was or not.

  She said now, "Why don't you ask me what you really want to know?"

  Disturbed, he said, "Very well. Mary—how does it feel?"

  She said slowly, "The same. Just... more. It's like coming fully awake—a feeling of clarity, of full consciousness. You must know. I've never been a scientist. But I've solved puzzles. I play chess, for instance. Science is something like that, isn't it? You figure something out—suddenly see how the game fits together—it's as if the clouds clear, just for a moment, and you can see far, much farther than before."

  "Yes," he said. "I've had a few moments like that in my life. I've been fortunate."

  She squeezed his hand. "But for me, that's how it feels all the time. Isn't that wonderful?"

  "Do you understand why people fear you?"

  "They do more than fear us," she said calmly. "They hunt us down. They attack us. But they can't damage us. We can see them coming, David."

  That chilled him.

  "And even if one of us is killed—even if I am killed—then we, the greater being, will go on."