They walked a little further, following the muddy shore.

In one place the lake bank was shallow, and easily climbed. Icebones clambered up that way. The land beyond was unbroken, harsh. But it was scarred by something hard and shining that marched from one horizon to the other: glimmering, glowing, an immense straight edge imposed on the world.

Icebones and Thunder approached cautiously. "It is a fence," he said.

"A thing of the Lost."

"Yes. A thing to keep animals out — or to keep them in."

That made no sense to Icebones. The land beyond the fence seemed just as empty and desolate as the land on this side of it. There was nothing to be separated, as far as she could see.

Thunder probed the fence with his tusk. Icebones saw that it was a thing of shining thread, full of little holes. The holes were too small to pass a trunk tip through, but she could see through the fence to what lay beyond.

And what she saw there was bones: a great linear heap of them, strewn at the base of the fence.

The mammoths walked further, peering up and down the fence, trying to touch the bones through the mesh.

"I don’t think any of them are mammoth," Icebones said.

Thunder said tightly, "The animals could smell the water. They couldn’t get through the fence. But they couldn’t leave; the world was drying, and they couldn’t get away from that maddening smell."

"So they stayed here until they died."

"Yes." And he barged the fence with his forehead, ramming it until a section of it gave way. Then he tramped it flat into the dust.

But there were no animals to come charging through in search of water; nothing but the dust of bones rose up in acknowledgment of his strength.

She tugged his trunk, making him come away.

From the lake came a soft crushing sound, a muffled trumpet.

The mammoths whirled.

Icebones looked first for the calf: there he was, safely close by his mother’s side, though both Breeze and Woodsmoke were standing stock-still, wary.

But of Autumn there was no sign.

Ignoring the pain in her straining lungs, Icebones hurried stiffly onto the ice. "Where is she? What happened?"

"I don’t know," Breeze called. "She was at the far side of the lake, seeing clearer water. And then—"

"Keep the calf safe."

Thunder immediately began to charge ahead.

Icebones grabbed his tail and, with an effort, held him back. "We may all be in danger. Slowly, Thunder."

He growled, but he said, "Lead, Matriarch."

Trying to restrain her own impatience, Icebones led Thunder and Spiral across the frozen lake, step by step, exploring the complex red-streaked surface with her trunk tip.

She heard a low rumble.

She stopped, listening. The others had heard it too. With more purpose now, but with the same careful step-by-step checking, the three mammoths made their way toward the source of the call.

At last they came to a wide pit, dug or melted into the ice. And here they found Autumn.

She lay on her side, as if asleep. But her body was covered with broad streaks of blood red, as if she had been gouged open by the claws of some huge beast. Her face, too, was hidden in redness, from her mouth to the top of her trunk.

"She is bleeding!" cried Spiral. "She is dead! She is dead!" Her wails echoed from the high rock walls of the valley.

But Icebones could see that Autumn’s small amber eyes were open, and they were fixed on Icebones: intelligent, angry, alert.

Icebones reached down and touched one of the bloody streaks with her trunk. This was not broken flesh. Instead she found a cold, leathery surface that gave when she pushed it, like the skin of a ripe fruit.

"This is a plant," she said. "It has grabbed onto Autumn, the way a willow tree grabs onto a rock." She knelt and leaned into the pit. She stabbed at the plant with her tusk, piercing it easily.

Crimson liquid gushed out stickily, splashing her face. The tendril she had pierced pulled back, the spilled fluid already freezing over.

The plant closed tighter around Autumn, and the Cow groaned.

Spiral touched Icebones’s dirtied face curiously and lifted her trunk tip to her mouth. "It is blood."

Thunder growled, "What manner of plant has blood instead of sap? What manner of plant attacks a full-grown mammoth?"

"She cannot breathe," Icebones said. "She will soon die…" She reached down and began to stab, carefully and delicately, at the tendrils wrapped over Autumn’s mouth. More of the bloody sap spurted. But the plant’s grip tightened on Autumn’s body, as the trunk of a mammoth closes on a tuft of grass, and Icebones heard the ominous crack of bone.

At last she got Autumn’s mouth free. The older Cow took deep, gasping breaths. "My air," she said now. "It sucks out my air! Get it off. Oh, get it off…"

Icebones and Thunder began to stab and pry at the bloody tendrils. The eerie blood-sap pumped out and spilled into the pit, and soon their tusks and the hair on their faces were soaked with the thick crimson fluid. But wherever they cut away a tendril more would come sliding out of the mass beneath Autumn — and with every flesh stab or slice the tendrils tightened further.

"Enough," Icebones said. She straightened up and, with a bloodstained trunk, pulled Thunder back.

Woodsmoke stood with Breeze a little way away from the pit. He trumpeted in dismay. "You aren’t going to let her die."

It struck Icebones then that Woodsmoke had never seen anybody die. She wiped her bloody trunk on the ice, then touched the calf’s scalp. "We can’t fight it, little one. If we hurt the blood weed it hurts Autumn more."

"Then find some way to get it off her without hurting it."

Thunder rumbled, from the majesty of his adolescence, "When you grow up you’ll learn that sometimes there are only hard choices, calf—"

But Icebones shouldered him aside, her mind working furiously. "What do you mean, Woodsmoke? How can we get the weed to leave Autumn alone?"

Woodsmoke pondered, his little trunk wrinkling. "Why does it want Autumn?"

"We think it is stealing her breath."

"Then give it something it wants more than Autumns breath. I like grass," he said. "But I like saxifrage better. If I see saxifrage I will leave the grass and take the saxifrage…"

Icebones turned to thunder. "What else could we offer it?"

Thunder said, "Another mammoth’s breath. My breath Icebones, if you wish it—"

"No," she said reluctantly. "I don’t want to lose anybody else. But what else…?"

Even as she framed the notion herself, Thunder trumpeted excitedly. "The breathing trees," they shouted together.

"Get the fruit," said Icebones. "You and Spiral. You are faster than I am. Go."

Without hesitation the two young mammoths lumbered over the folded ice toward the breathing trees, where they clung to the lake’s rocky shore.

Autumn moaned again. "Oh, it hurts… I am sorry…"

"Don’t be sorry," said Woodsmoke mournfully.

"It is my fault," Autumn gasped. "The plant lay over the pit. It was a neat trap… I did not check… I walked across it without even thinking, and when I fell, it wrapped itself around me… Oh! It is very tight on my ribs…"

"Don’t talk," said Icebones. Her voice lapsed into a wordless, reassuring rumble. Breeze joined in, and even Woodsmoke added his shallow growl.

Perhaps the pit had been melted into the ice by a stone, Icebones thought. Perhaps the blood weed, driven by some dark red instinct, had learned to use such pits as a trap. And it waited, and waited…

Autumn lay still, her eyes closed, her breath coming in thin, hasty gasps. But Icebones could see that the blood weed was covering her mouth once more.

This blood weed, like the breathing tree, was a plant of the cold and airlessness of the desiccated heights of this world. It was as alien to her as the birds of the air or the worms that crawled in lake-bottom mud — and yet it killed.