There was no real trail up the thousand-foot slope of Sentinel Mountain. Prospectors had been over it, doubtless, in earlier days, but in all of Garry's twenty-one years no one besides himself had ever made the ascent. There was nothing in all that solitary, desolate peak to call them; nothing, for that matter, to beckon Garry, except the hot desert days, the cool breath of evening and the glory of nights when the stars hung low over all the miles of sand and sagebrush that reached far out to the rippling sand-dunes shimmering in the distance. Nothing, that is, but the "feel" of the desert--and young Garry Connell was desert-born and bred. He stopped once and dropped his pack while he mopped his wet face. From this point he could see his own ranch spread below him. Miramar, he had named it--"Beautiful Sea." The name was half an affectionate mockery of this land where the nearest water was fifty miles away, and half because of the sea of blue that he looked at now. Garry had never ceased to wonder at the mirage. It was always the same in the summer heat--a phantom ocean of water. Garry's eyes loved to follow the quivering blue expanse that seemed so cool and deep. It rippled softly away to end in a line of white, like distant breakers on the horizon's rolling dunes. This had been the bed of an ocean in some distant past, and that ancient ocean could never have seemed more real than this; yet Garry knew that this sea would vanish with the setting sun. He had watched it often. * * * * * A hundred yards farther and he stopped again. It was no well-trodden path that Garry followed, but he knew his landmarks. There was the big split rock a half mile ahead, and the three-branched cactus beside it. But between these and the place where Garry stood was a fan-shaped sweep of boulders--and this where smooth going had been before. He forgot for the moment all discomfort. He stood staring under the hot sun that cast purple shadows beside the weathered rocks, and his eyes followed up the scarred mountainside. "That whole ledge that stood out up there--that's gone!" he told himself. "The whole side of the mountain just shook itself loose...." Far above, his eyes found another towering mass that reared itself menacingly. "That will come down next time," he said with conviction, "and I don't want to be under it when it breaks loose." Then his searching eyes found the lower ledge and its shattered remains. It had held a welter of rocks above it as a dam holds the pressure of water--and the dam had burst. The torrent of stone from above had swept into motion and carried with it the accumulation of loose rubble below. Where the ledge had been was now a cliff--a sheer wall of rock. It had been covered before by the talus that was swept away. Garry's eyes narrowed to see more plainly under the sun's glare. He was staring not alone at the cliff but at a shadow within it--a black shadow in the white face of the cliff itself.