* * * * * Two days later, Tyr parted the green fronds of a mountain bush and looked at the gleaming whiteness of the Barrow. It was a low rounded dome, lying across the hard whitish rocks of a strange mountain peak. From where he stood, he could make out arches receding back in under the dome, many of them. The arches were so many that each looked like a reflection of the others. The Barrow, he thought with dull triumph. It was camouflaged perfectly. That roundness gave no glint to a watcher in the sky. Its lowness cast no shadow. Its whiteness blended with the dazzling brilliance of the white mountain rocks. No wonder it had stood years without detection. Even looking for it as he was, Tyr almost missed it. Only the arches, seen at a certain angle, betrayed its existence. He loped toward it, breaking into the open. Only when he was near the arches did he see the woman on the ground to one side, kneeling. Before her a man lay on his back. Tyr went forward on the tips of his toes, as silent as a breeze moving across rock. The girl knelt beside the man, was moving her hands over him swiftly, competently. Then she leaned back on her haunches and shook her dark head. The black blouse and white slacks looked familiar. When he saw her face as she raised it, he knew. "Katha," he said. The girl whirled, reaching for a gun at her hip. But when she saw him fully she gave a low cry and scrambled to her feet. "Tyr, Tyr! Oh, I'm so glad I've found you!" And was running to him. He tried to be curt, but it was useless. There was too much joy shining out of those black eyes, too much laughter and delight. And she was so feminine! He put out his hands and held her arms, making her stay a little away from him. Tyr wondered if she heard the wild pounding of his heart. "Why?" he asked. "Why are you here? Why did you come searching for me?" Laughter was like musical hoarseness in her throat. With head flung back so that she could hold him with her eyes, she said, "Because Space Commander Mason ordered that you be shot on sight. Because you are a doomed man. And because--I think you may yet save the Trylla." "You are _ardth_!" "It makes no difference. What are you, for that matter?" "I--I don't know." He did not know. Always that uncertainty tugged at the core of him. Unknowingness within him, like an emptiness. Who are you, Tyr? What are you? And mad laughter answered, "You do not know. You will never know what you are. A god? Ho! Not you, not Tyr." She saw the blankness in his eyes, and the misery. Her voice was soft, tender. "Tyr, can't you see? You are--Tyr." He shook his head, heart dull within his chest. She cried between a laugh and a sob, "But you are the first, Tyr, the first of your kind! I can tell you that. You are a biochemical newcomer." "What does that mean?"