Mark broke the stare and looked again at the boys, who were climbing steadily and coming to the thicker growths. Soon they were invisible among the trees.

"They'll get lost," he said.

Bruce shrugged. "Not in one hour or two," he said. "At noon they'll eat, turn around, and come back."

The sky was deep blue with puffs of white clouds and a very high band of cirrus clouds with no apparent beginning or end. It would be noon in less than two hours.

Stubbornly Mark shook his head, but he said nothing more. He returned to class, and then went to the dining room for lunch. After lunch he was due to work in the garden for two hours, and he was there when Barry sent for him.

"They aren't back yet," Barry said when Mark entered the office. "Why were you so certain they would be lost?"

"Because they don't understand about the woods," Mark said. "They don't see things."

"What things?"

Mark shrugged helplessly. "Things," he said again. He looked from one brother to another and again shrugged.

"Could you find them?" Bruce asked. His voice sounded harsh, and deep frown lines cut into his forehead.

"Yes."

"Let's go," Barry said.

'The two of us?" Mark asked.

"Yes."

Mark looked doubtful. "I could do it faster alone," he said.

Barry felt a shudder start, and drew himself away from his desk with a brusque motion. He was holding himself rigidly under control now. "Not you alone," he said. "I want you to show me those things you see, how you can find your way where there's no path. Let's go before it gets any later." He glanced at the boy in his short tunic, barefooted. "Go get changed," he said.

"This is all right for up there," Mark said. "There's nothing under the trees up there."

Barry thought about his words as they headed for the woods. He watched the boy, now ahead of him, now at his side, sniffing the air happily, at home in the silent, dim woods.

They moved quickly and very soon they were deep in the forest where the trees had reached mature growth and made a canopy overhead that excluded the sun completely. No shadows, no way to discover directions, Barry thought, breathing hard as he worked to keep up with the nimble boy. Mark never hesitated, never paused, but moved rapidly with certainty, and Barry didn't know what clues he found, how he knew to go this way and not that. He wanted to ask, but he needed his breath for climbing. He was sweating, and his feet felt like lead as he followed the boy.

"Let's rest a minute," he said. He sat on the ground, his back against a mammoth tree trunk. Mark had been ahead of him, and now he trotted back and squatted a few feet away.

"Tell me what you look for," Barry said after a moment. "Show me a sign of their passage there."