Pebble's home was a kind of village, with four large huts set roughly around a clearing. And yet it was not a village, for his people lived not quite as any humans ever would.

Pebble stood, panting, in the central clearing. Nobody was around. Close to the door of one hut a fire smoldered. The trampled ground was scattered with bone, vegetable debris, tools, mattresses of leaves and grass, trays of bark, pegs, wedges, a broken spear, discarded bits of leather. The place was a mess.

The huts were crude and ugly, but serviceable. They had been built of thick saplings set in rough circles in holes in the ground. The gaps between the saplings were filled with rattan cane split into switches, and overlapping leaves, bunches of rushes, bark. The saplings were bent over together and their ends pushed over and under each other. It was a kind of weaving that Capo would have recognized, for five million years earlier he had made his treetop nests in much the same way: Every innovation of necessity was built on what had gone before.

The huts were old. The people had lived here for generations. The dirt beneath Pebble's feet was thick with the bones of his ancestors. The people felt safe here. This was their place, their land.

But now, Pebble knew, all that might change.

He raised his head to the washed-out sky. " U-lu-lu-lu-lu! U-lu-lu-lu-lu! U-lu-lu-lu-lu! U-lu-lu-lu-lu!..." It was a cry of danger, of pain, the first cry any child learned after the feed-me yell.

Soon the people came running, from the huts, from the land beyond where they foraged and hunted. They gathered around Pebble in concern. There were twelve of them: three men, four women, three older children- including Pebble himself- and two infants in their mothers' frightened grasp.

He tried to tell them what he had seen. He pointed back to where he had seen the strangers, and ran a few paces back and forth. "Others! Others, others, hunters!" He began an elaborate performance, gesticulating, posturing, puffing himself up to walk like powerful hunters, even miming to show how they would smash in the people's heads with their mighty fists.

His audience were impatient. They turned away, as if eager to return to their foraging, or eating, or sleeping. But one man watched Pebble's performance more carefully. He was a squat man even more powerfully built than most, and his face was distorted by a childhood accident that had smashed the cartilage in his great fleshy nose. This man, Flatnose, was Pebble's father.

Pebble's language was sparse. It was just a string of concrete words with no grammar, no syntax. And, a million years after Far, talking was still basically a social skill, in fact used mainly for gossip. To convey detail or complex information, you had to repeat, use endless circumlocution- and mime, gesture, perform. Besides, Pebble had to convince his audience. It was hard for the adults to accept what Pebble had to say. They couldn't see the strangers for themselves. He might be lying or exaggerating: He was, after all, little more than a child. The only way they had to gauge his sincerity was by the passion and energy he put into his performance.

It was always this way. To get anyone to listen, you had to shout.

At last Pebble gave up, panting, and sat squat in the dirt. He had done his best.

Flatnose kneeled beside him. Flatnose believed his son: His performance had cost him too much to be lies. He rested his hand on his son's head.

Reassured, Pebble touched his father's arm. There he found a series of scars, long and straight, following the line of the forearm. These scratches were the marks of no animal. Flatnose had inflicted them on himself, with the sharp blade of a stone knife. When he was older, Pebble knew he would join in the same game, the same silent, grinning self-mutilation: It was part of what his father was, part of his strength, and Pebble found it reassuring now to stroke those scars.

One by one the other adults joined them.

Then, the moment of silent acceptance over, Flatnose got to his feet. There were no words now. Everybody knew what had to be done. The adults and the older children- Pebble and a girl a little younger than himself- started to move around the settlement, gathering weapons. There was no particular order to the settlement, and weapons and other tools lay where they had last been used, amid piles of food, debris, ash.

Despite the urgency the people moved sluggishly, as if even now reluctant to accept the truth.

Dust, Pebble's mother, tried to soothe her squalling baby as she gathered up her gear. Her loose, prematurely grayed hair was, as always, full of dry, aromatic dust, an eccentric affectation. At twenty-five she was aging quickly, and she limped when she walked, the effect of an old hunting wound that had never healed right. Since then Dust had had to work twice as hard, and the cumulative effect showed in her stooped posture and careworn face. But her mind was clear and unusually imaginative. She was already thinking of the difficult times ahead. Watching her face, Pebble felt guilty at having brought this trouble down on her.

There was a soft sigh, a flash. Pebble turned.

In a dreamlike moment, he actually saw the wooden spear in flight. It was hewn from a fine piece of hardwood, thickest near the point and tapered back toward the other end, shaped to make it fly true.

Then it was as if time began to flow again.

The spear slammed into Flatnose's back. He was thrown to the ground, the spear sticking straight out of his back. He shuddered once, and a burst of shit cascaded from his bowels, and a black-red pool spread under him, soaking into the dirt.

For a heartbeat Pebble couldn't take this in- the thought that Flatnose had gone so suddenly- it was as if a mountain had suddenly vanished, a lake evaporated. But Pebble had seen plenty of death in his young life. And already he could smell the stink of shit and blood: meat smells, not person smells.

A stranger was standing between the huts, squat and powerful. He was wrapped in skins, and he held a thrusting spear. His face was daubed with crosshatched ocher marks. He was the one who had hurled the spear at Flatnose. And Pebble saw his own abandoned digging stick in the stranger's hand. They had seen him at the yam stand. They had tracked his footsteps. Pebble had led them here. Pebble had led them here.

Full of rage, fear, and guilt, he hurled himself forward.

But he went clattering to the ground. His mother had grabbed his waist. Lame or not she was still stronger than he was, and she glared at him, jabbering, "Stupid, stupid!" For an instant sanity returned to Pebble. Naked, unarmed, he would have been killed in an instant.

A man burst out of the heart of the settlement. He was naked and he carried his own thrusting spear. He was Pebble's uncle, and he hurled himself at the killer of his brother. The stranger fended off the first blow, but his assailant closed in. The two of them fell to the dirt, wrestling, each trying to get in a decisive blow or thrust. Soon they had disappeared in a cloud of blood-spattered dust. They were two immensely muscled beings using all their mighty strength against each other. It was like a fight between two bears.

But more of the hunters came boiling out of the cover of the rock bluffs and trees. Men and women together, all armed with spears and axes; they were dirt-crusted, lean, hard-eyed. They had come hunting Pebble and his group, as if they were a herd of unwary antelope.

Pebble could see desperation in the eyes of the others. These newcomers were not nomads, not invaders by instinct, any more than Pebble's people would have been. Only a dire catastrophe of their own could have forced them to this plight, to make them come into a new and strange land, to wage this sudden war. But now that they were here, they would fight to the death, for they had no choice.

There was a howl. The hunter who had taken on his uncle was standing now. One arm dangled, bloody and broken. But he was grinning, his mouth a mass of blood and broken teeth. Pebble's uncle lay at his feet, his chest split open.

Already Pebble's folk had lost two of their three adult men, Flatnose and his brother. They had no chance of resisting.

The survivors ran. There was no time to grab anything, no tools or food- not even the children. And the hunters fell on them as they fled, using the butts of their spears to fell and disable. The third man was cut down. The hunters caught two of the women, and the girl younger than Pebble. The women were thrown to the ground, face first, and the young men pulled their legs apart, jostling for the right to be first.

The others ran, on and on, until the pursuers gave up.

Pebble looked back the way they had come. The hunters were pawing through the settlement, the ground that had been Pebble's ancestors' for time out of memory.

There were five of them left from the village, Pebble realized. Two women, including his mother, Pebble himself and a smaller girl, and one of the infants- not Pebble's sister. Just five.

Her face hard, Dust turned to Pebble. She laid a hand on his shoulder. "Man," she said gravely. "You."

It was true, he saw with horror. He was the oldest male left: of the five, only the squalling infant in the dirt at his feet was male.

Dust scooped up the motherless infant and held him close. Then she turned resolutely away from her settlement and began to stomp away to the north, her lame gait leaving uneven tracks in the dirt. She didn't look back, not once.

Bewildered, terrified, Pebble followed.

II.

The Pleistocene, this era of ice, was an age of brutal climatic turbulence. Droughts and floods and storms were commonplace: in this age a "once-in-a-century" climatic disaster came around every decade. It was a time of intense variations, a noisy time.

This created an environment that was intensely challenging for all the animals who inhabited it. To cope with the changes many creatures got smarter- not just hominids, but carnivores, ungulates, and others. The average mammalian brain size would double across the two million years of the Pleistocene.

The great family of hominid species to which Pebble belonged had been born in Africa, as had so many others, far to the south of here. Smarter, stronger than Far's folk, they had pushed in a great arc out of Africa into Europe, south of the ice, and into Asia, as far as India. They had adapted their technology, their ways, and, over enough time, even their bodies to the disparate conditions they encountered.

And they had displaced the older forms of people. Elegant, skinny walkers like Far still survived in eastern Asia, but they clung on in Africa only in pockets. In Europe they were extinct altogether. As for the pithecine types, the last of them had succumbed long ago, squeezed out between the chimps and the new savannah folk. Still, the hominid range was narrow. There were still no people in the cold northern lands, none in Australia, and none in the Americas, none at all. But the Old World felt ever more full of them.

Meanwhile the land was growing poorer.

Once more there had been extinctions. And this time the people had had a lot to do with it. Under climate pressure, many of the larger, slow-breeding species of animals had found themselves increasingly tied to the water sources. They therefore became an easier target for increasingly clever hominid hunters, who, looking for the lowest-risk kills, selectively picked off the old, the weak- and, crucially, the very young.

The largest and least versatile species had been taken out first. In Africa, of the wide and ancient elephantid family, only the true elephants remained. Many varieties of giraffe, pig, and hippo had followed.

And then there was fire.

The harnessing of fire, not so many generations before Pebble's time, had been one of the most significant events in hominid evolution. Fire offered many advantages: warmth, light, protection from carnivores. It could be used to harden wood, and its heat could be used to make many plant and animal foods digestible. There was still no organized large-scale firing and ground clearing; that would come later. But already the daily use of fire had had, little by little, a profound impact on the vegetation, as those plants able to withstand fire were favored at the expense of less hardy cousins. And meanwhile, though true agriculture lay far in the future, hominids had begun to select those plant species they favored for their own purposes- just as Pebble had cleared grass from the yam stand.

Such small actions, repeated every day across hundreds of thousands of years, had an immense impact. Once the landscape had been shaped by the trampling of elephants: Far and her kind had been marginal. Not so now. This landscape had been made by people.

By now it was as if this bare landscape of fire-resistant trees and sparse grass-eaters were somehow natural, and had been here forever, for all time. It had been this way so long that no mind on Earth could remember how things might have been different.

Seal had caught a spider on the beach. He scampered over the sand and brought it to Pebble, grinning. "Spider web spider fish." Pebble tapped Seal on the head, warming to his infectious energy, and wishing he shared some of it.

Seal ran back to the clump of dune grass where he had found the spider. The web was built on a fan of strong radial lines, over which the spider had laid a spiral of continuous sticky web. Now- delicately, delicately, holding a small stick in his wide fingers- the boy lifted the spiral off its nonsticky guide ropes. He moved the rod spoke by spoke, twirling it so that the sticky stuff formed a dangling mass at the end of the rod. Then he hurried to a tidal pool, sheltered by lumpy, eroded rocks. He put his stick in the water, letting the sticky mass dance on the water's surface.

A tiny fish came to nibble the enticing lure. But with every bite its jaws got stuck more firmly in the web. At last it was glued to the stick and was easily scooped out of the water. Seal popped it straight into his mouth with a grin of triumph. Then he dipped his makeshift rod into the dead spider's glue sac and settled it back into the water.

Seal, brought out of the abandoned settlement in the arms of Dust eleven years back, was twelve years old now- seven years younger than Pebble himself. His early years had been quite different from Pebble's: They had been years on the move. But Seal didn't seem disturbed by his experiences. Perhaps he had got used to migrating, like one of the big grass-chewers that followed the seasons. And he had taken to the ocean. He was too heavy to swim- they all were- but whenever Pebble saw him in the shallow water close to the shore, he was reminded of a playful mammal of the sea.

But, eleven years after the trauma of the attack that had killed his father, Pebble had nothing in common with Seal's inventive playfulness.

At nineteen Pebble was fully mature, his frame as squat and powerful as his father's had been. But he was battered. His body bore old scars from ferocious, desperate hunting incidents. In a collision with a wild horse he had suffered a cracked rib that had never healed properly, and for the rest of his life he would suffer a diffuse pain every time he took a breath. And he bore the marks of wounds inflicted by people; too often he had had to fight.

Forced to grow up too quickly, he had become introspective. He hid his thoughts behind a mass of beard that, year after year, became more dense and knotted, and his eyes seemed to recede beneath their great browridge of bone.

And, like his father, on each of his arms he bore long, ragged scars.

With a sigh Pebble returned to his own gloomy inspection of the nets and lures he had strung out in the deeper water. This pebbly beach was protected from the sea by an outstretched arm of land, and a freshwater stream trickled down over the beach from the base of the bluffs. The sea was the Mediterranean: This was Africa's northern coast. Behind him, to the south, the land rose up in a series of bluffs. It was here that Pebble's refugee people had at last made their home, on the dry grassy dunes above the high-water mark, in a hut constructed from driftwood and saplings.

As far as he knew Seal, playing with spiders and their webs, had come up with his own miniature way of fishing. But then, on this dismal shore, they had all been forced to learn fast about the use of the sea. In the early days there had been much splashing around as hunters used to chasing down antelope had hurled themselves through the shallows after darting fish and dolphins that evaded them easily. They had gone hungry, and despaired.

They had got the right idea, in the end, from watching the spiders, and the birds and small animals that occasionally got tangled up in bushes or canes with sticky foliage, or in thickets with trailing vines.

Gradually they had figured out the use of nets and traps and snares, woven from bark and bits of leather. Their first attempts had failed more often than not. But they had slowly developed skills in exploiting natural cords and vines, and learned how to weave, repair, and tie fibers. And it worked. If you were lucky you could trap fish, octopus, and turtles. The deeper into the water you went, the better the catch would be.

Well, it had had to work. Otherwise they would surely have starved.

Ironically the land to the south, beyond these coastal bluffs, was rich, a mosaic of woodland and grass and fresh- and saltwater pools. And there were plenty of animals, beyond the marshes and on the higher ground: red deer, horse, and rhinoceros, and many smaller herbivores. Sometimes the animals would even come down to the beaches in search of salt.

If the land had been empty of people it might have been a paradise for Pebble's group. But the land was not empty, and that was the entire trouble.

On the horizon there was an island. His gaze was drawn there now. Though it was made misty blue by distance, even from here he could see how rich the island was, with lush vegetation running down every cleft of rock, almost to the ocean. And there were people there. He had seen them on clear days: skinny, tall people, who would run across their beaches and hilltops, pale flitting figures.

There he and his people would be safe, he thought. On an island like that, a scrap of land of their own, they could live forever, untroubled by strangers. If he could get there, perhaps he could fight those skinny folk for possession of their land.

If he could get there. But people could not swim like dolphins, and they could not walk over the water like insects. It was forever impossible. he could get there. But people could not swim like dolphins, and they could not walk over the water like insects. It was forever impossible.

So here they were, stuck.

They had never planned to come so far as this. None of them had planned any of this at all. They had just been forced to keep going, and going, while the years had worn away.

Pebble's kind were by nature sedentary; these robust folk had long lost the wanderlust of Far's day. It had stressed them hugely to be thrust into unfamiliar landscapes: For Pebble it was as if the great trek had been a long, slow breakdown, a time of madness and bewilderment.

During the journey the children had grown- Pebble himself had become a man- and their numbers had slowly risen, as more refugees from one disaster or another tagged along with them. And their numbers had grown in another way. Pebble had become a father; he had coupled with Green, the wistful woman who had come with them from the old settlement. But as they crossed a particularly harsh and dry land, the child had died.

And still they had found nowhere they could live. For the world was full of people.

Before the attack there had been twelve people in Pebble's close extended family. They were self-sufficient, and very sedentary. They did not trade, never traveled much further than could be reached in a day's walk.

But they had been aware of similar groups nearby, studded around the landscape, as immobile as trees.

In all there were over forty tribes in the larger clan of which Pebble's people were part, around a thousand people. Sometimes there would be exchanges as youngsters from one "village" sought mates in another. And there was occasional conflict as two parties found themselves competing over a rich foraging ground or the target of a hunt. But such incidents were usually settled with nothing much more than a slanging match, some inconclusive wrestling, and in extreme cases a spear in the leg, a maiming which had evolved as a ritual punishment.

And every one of this thousand-strong band, from the smallest baby to the most wizened thirty-five-year-old crone, was marked with the characteristic red or black vertical stripes that Pebble still wore on his face.

Far would have been astonished to see what had become of her innocent innovation with the bits of ocher. What had started out as a half-unconscious sexual deception had become, over immense stretches of time, a kind of looser celebration of fecundity. Women and even some men would mark their legs with the characteristic color of fertility. Slowly, dim minds and fumbling fingers had experimented with other forms of markings, new symbols.

By now, though, this crude scribbling had a purpose. Pebble's vertical markings were a kind of uniform, setting a boundary between his folk and others. You didn't need to remember everybody in your group personally- as Capo had had to when he had tried to lead his followers. You didn't need to know faces. All you needed was the symbol.

The symbols united the bands. In a way the symbols had become what they fought for. These crude stripes and body markings were the birth of art, but they were also the birth of nations, the birth of war. They would make possible conflicts that would transcend even the deaths of those who had started them. That was why hominid minds were becoming smarter at creating the symbols, with each new generation.

All across this landscape there were clans like this, clans of more or less the same size. They were all sedentary, all staying where they had been born, where their parents and grandparents had lived and died. Their languages were mutually incomprehensible. Indeed many of these communities were no longer even able to interbreed, so long had they been isolated. And there they stayed, until they were displaced by some natural catastrophe like a climate shift or a flood- or by other people.

Which was why the clans had formed in the first place, of course: to keep out the refugees.

It had been terribly hard for them. At last, after eleven years, they had come to this place, this beach, and they had been forced to stop, for here the land had run out.

Now Pebble heard a mournful cry from up the beach. "Hey, hey! Help, help!"

Pebble stood and peered that way. He saw two stocky figures staggering toward the hut. They were Hands and Hyena, the one characterized by his huge, powerful hands, the other by his habit, when hunting, of laughing like a scavenger. These two men had joined Pebble's group during their long odyssey. But now they were struggling. Hyena was leaning heavily on the powerful shoulders of his companion, and even from here Pebble could hear Hyena's wheezing gasps.

Dust came out of the hut. Pebble's mother, in her late thirties now, had grown gaunt and bent with the stresses her body had endured during the long walk, and her hair was white and wispy. But she was still doggedly alive. Now she began to hobble up the beach toward Hyena and Hands, and called out. "Stab, stab!"

Hyena collapsed to the beach, and Pebble could see a stone blade sticking out of his back. Hands struggled to get him to his feet again.

Muttering darkly Pebble stalked across the beach after his mother.

By the time they had brought Hyena back to the hut, the light was beginning to leave the sky.

Preparing themselves for the tasks of the night, the people moved around the hut. The men and women alike had immense bulging shoulder muscles that showed humplike through their leather wraps. Even their hands were huge, with broad spadelike fingertips. Their bones were thick-walled, capable of enduring great stress, and their joints were heavy and bony. These were massive people, solid, as if carved out of the Earth themselves.

They had to be strong. In a tough environment, they had to work very hard all their lives, making up in brute force and endless labor what they lacked in smarts. Few reached the end of their lives without the pain of old wounds and such problems as degenerative bone diseases. And hardly anybody lived beyond forty.

Hyena's wound was unremarkable. Even the fact that he had clearly been stabbed in the back by a hominid from a rival band beyond the bluffs did not arouse much interest. Life was hard. Injuries were commonplace.

Inside the low, irregular, poky hut there was no light save from the fire and whatever daylight leaked through the gaps in the plaited walls. There was little organization. At the back of the hut were piled up bones and shells, discarded after meals. Tools, some broken or just half-finished, lay where they had been dropped, as did bits of food, leather, wood, stone, unworked skin. On the floor could be spotted traces of the staples that the group relied on: bananas, dates, roots and tubers, a great deal of yam. The adults did dump their feces and urine outside, to keep out the flies, but the younger children had yet to learn that trick, and so the floor was littered with half-buried infant shit.

There weren't even any fixed places for the fires. The scars of old fires were visible across the floor of the hut and outside in the blackened circles of scuffed pebbles and sand. When the wind changed or a part of the hut collapsed, they would just move the embers from yesterday's fire to a new place and start again.

A human would have found the hut dark, low, claustrophobic, cluttered, disorganized, and filled with an unbearable stench, the stench of years of living. But to Pebble this was just the way things were, the way they always had been.

There were actually two fires being tended tonight. Hands had turned to the hot fire that had smoldered all day. He prowled around the settlement gathering bits of dried wood, and he carefully built up a pyramid of wood and chips to make a more intense, hotter fire. He had stripped the flesh off the head and limbs of a baby rhino, and now he would use his fire to crack the bones and get at the rich marrow inside.

Toward the rear of the hut, Dust and the woman Green were working on a second fire with Seal and Cry and some of the children. They had a handful of stones which they knapped quickly to make knives and borers, and with these they worked the food they had managed to gather during the day within a few hundred meters of the hut. This included shellfish- even a rat.