But Jahna had looked up. A wall of wind-driven snow was descending on them, turning the world white.

Jahna grabbed Millo’s hand and dragged him into the shelter of an obtruding block of ice. They huddled up against the ice, knees tucked against their chests. The wind screamed through hollows and flutings in the ice, too loud for her to hear her own voice, too loud to think.

Then the snow was on them.

She could see nothing but white — no sea, no horizon, no sky. It was as if they had been thrust inside an egg, she thought, a perfect, closed-over egg, sealed off from the world.

Soon the snow was sticking to their furs and piling up against the ice wall. She knew there was a danger that the snow would drift, here in the lee of this boulder, and she tried to clear away the gathering layers of sharp white crystals.

But the storm went on, and on. And with every heartbeat that passed, the chances were that Rood and the others were getting farther and farther away.

Millo’s patience ran out. He pushed her away and stood up, but the swirling wind almost knocked him off his feet. She pulled him back down.

“No!” he screamed through the wind, struggling. “We’ll die if we stay here.”

“We’ll die if we leave,” she yelled back. “Look at the snow! Listen to the wind! Think — which way is the land?”

He turned vaguely, his small round face battered by the snow.

“We already made a bad mistake,” she said. “We didn’t see the storm coming. What does your soul tell you to do? What does Millo, your great-grandfather, tell you?” She could probably have overpowered him, just forced him to stay, but that would have been wrong. She had to convince him to stay put. For if he chose to leave — well, that was his prerogative.

At last he relented. With tears freezing to his cheeks he dropped back to the ice and huddled up against his sister. She held him until the weeping was done.

She kept up her routine of clearing off the loose snow. But as darkness fell — as the bubble of white turned gray, then black, with no letup in the storm — she became increasingly weary, hungry, and thirsty.

At last she couldn’t fight off the sleep any longer. Just for a while, she thought; I will rest just for a while, and wake before the snow gets too thick. She dreamed of rocking, as if she were an infant in her father’s arms.

When she woke she felt the weight of her brother’s head on her lap. The noise of the storm was gone. She was in darkness; but it was warm here, dark, warm, safe. She closed her eyes and settled back. It would surely do no harm to rest a little longer.

But now Millo gasped, as if struggling for air. She remembered his dream, of darkness and immersion and drowning. Maybe she was in the same dream now.

Darkness.

In sudden panic Jahna pushed Millo away. Reaching up, she felt a thick layer of loose snow above her. She forced herself to her feet, pushing her face through the clinging snow.

And found herself in dazzling light. She gasped in the sudden richness of the clean, cold air. The sky was a perfect deep blue dome through which the sun sailed. She gazed around at a landscape of jumbled ice blocks embedded in blue-gray pack ice, scattered with frost and snow drifts, all of it unfamiliar. She was waist-deep in snow. She had been lucky to wake when she did, she knew; the drifting snow had kept her warm, but had nearly suffocated her.

She reached down, pushing away the snow, until she found Millo’s shoulders. She hauled him out into the air. Soon he was blinking in the light and rubbing his eyes. The snow where he had been lying had turned piss-yellow. “Are you all right?” She cleared the snow from his hair and face, took off his mittens and manipulated his fingers. “Can you feel your toes?”

“I’m thirsty,” he said plaintively.

“I know.”

“I want Rood. I want Mesni.”

“I know.” Jahna was furious with herself. Careless, careless again, to have fallen asleep like that. And it was carelessness that might yet cost Jahna her life and Millo his. “Let’s get back to the headland.”

“All right.”

She put on her mittens and took his hand. They walked around the ice block that had sheltered them, back the way they had come yesterday. There was no headland. She could make out the land, but it was a low, worn-looking shore, blanketed by a crisp layer of unbroken snow.

Millo moaned, “Where’s Rood?”

For a time Jahna struggled to accept what she was seeing. Everything had been made unfamiliar by the spring storm. And her knowledge of the land was not as deep as her father’s. But still she could see that that was not the shore she had left before the storm. Give me strength, Jahna, mother of my father. “I think the pack ice must have broken up during the storm. We drifted over the sea—” she remembered now those dreams of languid rocking ” — and finished up here.”

“I don’t recognize that place,” Millo said, pointing to the land.

“We must have been carried a long way.”

“Well,” Millo said, businesslike, “that’s where we’ve got to go. Back to the land. Isn’t it, Jahna?”

“Yes. That’s where we’ve got to go.”

“Come on then.” He took her hand. “This is the way. Watch your step.”

She let him lead her.

They trekked along the coast. Blanketed by the snow, the land was silent. Hardly anything moved — just an occasional arctic fox, a bedraggled gull, an owl — and the quiet was eerie, unnerving.

It was difficult walking through the heaped-up snow, even close to the shore, especially for Millo with his shorter legs. They had no idea where they were, no idea how far the drifting ice might have carried them. They didn’t even know if they were walking back the way they had come, toward the headland. At that they were lucky, Jahna reflected with a shudder, that the ice floe hadn’t simply carried them out to sea, where, helpless, they would quickly have frozen to death.

They found a stream running fast enough to have stayed clear of this unseasonal snow. They bent to drink, up to their elbows in snow, their breath steaming. Jahna was relieved. If they had not found fresh water they might have been forced to eat snow. That would have quenched their thirst but it would have put out the fire that burned inside their bodies — and, as everybody knew, when that happened, you died.

Water, then. But they found no food, none at all. They walked on.

They stuck to the coast, feeling unwilling to penetrate that central inland silence. There were many dangers there — not the least of which were people.

As primates with bodies built for tropical climes strove to survive the rapidly changing extremes of the Pleistocene, they had built on the ancient traits they had inherited from the wordless creatures of the forests: on bonds of kinship and cooperation.

The clans scattered over Eurasia and Africa lived in almost complete isolation from one another. And the isolation went very deep. Fifty kilometers from Jahna’s birthplace lived people who spoke a language more different from hers than Finnish would be from Chinese. In the days of Far and even Pebble, there had been a transcontinental uniformity; now there could be significant differences between one river valley and the next. Humans were capable of altruism so generous one would suffer injury, maiming, even death to save another — and yet they indulged in extreme xenophobia, even deliberate and purposeful genocide. But in a harsh land where food was short, it made sense for members of a community to support one another selflessly — and to fend off others, who might steal scarce resources. Even genocide had a certain horrible logic.

If the children were discovered by strangers, it was possible Jahna’s life would be spared — but only so she could be taken for sex. Her best hope would be to fall pregnant, and win the loyalty of one of the men. But she would always be lowly, never one of the true people. Millo, meanwhile, would simply be killed, perhaps after a little sport. She knew this was so. She had seen it happen among her own kind. So it was best they remain undiscovered.