He bent over the man, reaching for his wrist. The pulse was weak but steady. He had given the Tibetan a healthy belt. There was no sign of returning consciousness. But Rick wasn't worried. If he had hurt the man badly, the pulse would have been thready and unsteady. He would wake up presently, and his head would feel like a pillow stuffed with rocks, but otherwise he would be all right. Rick knew. He had been knocked out himself a couple of times. He resumed rowing, and his steady strokes brought him closer to the opposite shore. He turned to examine it and saw that a rocky ledge rose gradually out of the water. In a short time he felt the boat grind against the limestone. He got out and pulled the craft up on the shore, which was worn smooth by the water. The ledge varied from ten to fifty feet in width. Beyond it, the roof of the cavern came down sharply to form a curving wall broken in countless places. He could see into the broken places nearest him. They were the beginnings of more cave labyrinths. Now that he had reached the opposite shore, what was he to do? Again he leaned over the Tibetan. The man showed no signs of returning consciousness. Rick cast his invisible light up and down the shore. Nothing indicated that humans ever had been there before him. He realized that the wisest thing would be to wait until his guide returned to consciousness and then force him to lead the way once more. But he was impatient. Somewhere along the shore there must be signs he could follow. He pulled the boat up as high as he could, then used strips torn from the Tibetan's own clothes to bind and gag him. That done, he picked up the infrared camera and his rifle and stood a moment in indecision. Which way? It was a tossup. Finally he decided to keep going in the general direction the Tibetan had led him. He paused long enough to inspect his rifle. After firing, he had failed to lever another cartridge into the chamber. He did so now, then put the hammer on half cock so it couldn't fire accidentally, and started off. It was easy going in most places. But now and then he came to a point where the shore ledge narrowed and he had to crawl. Once he skirted an outcropping by walking in the water, feeling his way carefully so he wouldn't step off a ledge into the depths. After a while he began to think he hadn't been very smart. He was getting exactly nowhere. As far ahead as the infrared beam could penetrate, there was nothing but the curving shore. In some places the lake narrowed to a channel less than a hundred feet wide, then it broadened again until he could no longer see the opposite shore. He couldn't guess how far he had walked from the boat. He thought it must be at least a quarter mile.