At the gap over the trail he hesitated. That path ran in the direction of the open, and to go on foot meant the possibility of greater speed. Vye slipped from the bough, hit the ground, and ran. His ragged lungsful of air came in great gasps and he doubted if he could take the exertion of more tree travel now. He raced down the path. Those mewling cries were louder, he was sure of it. Now he heard the thump of the beast's blundering pursuit behind him. But its bulk and hurts slowed it. In the open he could find cover behind a rock, use the ray again. The trees began to thin. Vye summoned power for a last burst of speed, came out of the shadow of the wood as might a dart expelled from a needler. Before him, up slope, was the closed door of the valley. And moving in from the left was another of the blue beasts. He could not retreat to the trees. But the newcomer was moving with the same ponderous self-confidence its fellow had shown earlier. Vye dodged right, headed for the rocks by the gap. As he pulled himself into that temporary fortification, the wounded beast dragged out of the woods below. He thought it was blind, yet some instinct drove it after him. Shaking from fatigue, Vye steadied his forearm on the top of the rock, brought up the ray tube. Less than two yards away now was the deceptively open mouth of the gap. If he threw himself at that, would the elasticity of the unseen curtain hurl him back into the claws of the enemy? He fired his blast at the head of the unwounded beast. It screeched, threw out its arms, and one of those paws struck against its wounded fellow. With a cry, that one flung itself at its companion in the hunt, and they tangled in a body-to-body battle terrible in its utter ferocity. Vye edged along the cliff determined to reach the cave and Hume. And the two blue things seemed intent on finishing each other off. The one from the wood was done, the fangs of the other ripping out its throat. Tearing viciously the victor made sure of its kill, then its seared head came up, swung about to face Vye. He guessed it was aware of his movements whether it could see or not. But he was not prepared for the speed of its attacking lunge. Heretofore the creatures had given the impression of brute strength rather than agility. And he had been almost fatally deceived. He jumped backwards, knowing he must elude that attack, for he could not survive hand-to-hand combat with the alien thing. There was a moment of dazed disorientation, a weird sensation of falling through unstable space in which there had never been and never would be firm footing again. He was rolling across rock--outside the curtain of the gap. He sat up, the feeling of being adrift in unmeasurable nothingness making him sick, to watch mistily as the blue beast came to a halt. Whimpering it turned, but before it reached the level of the woods, it sagged to its knees, fell face forward and was still, a destructive machine no longer controlled by life.