Uncertain which way to go, he stood for a moment outside the flap of the tent. The rim of the saucer-shaped valley lay straight ahead. Beyond were the great white snow wastes, stretching mile on mile, isolating the little camp more effectually than a quarantine. He decided to climb out of the draw and push across the hilltops. To his ears came a faint slithering sound. He listened, heard it again. The crunching of a ski on crusted snow! Who could be out at this time of night? Why? For what purpose? It was probably one of the men, he reflected. But none of them would be on skis to move over the beaten paths around the camp. Some sixth sense warned of danger in the vicinity. He crept around the tent in the direction from which the sound had come. His glance took in the other tents, scarcely visible against the background of white in the dim light of pre-dawn. Everything there was still and silent. Again there came to him the hiss of a ski. A hundred yards distant was the mouth of the tunnel. A moving figure stood out, black against the pale background. Some one who had obviously just emerged from the tunnel was shuffling away through the snow. Hollister did not shout an order to halt. Instinctively he knew that something was wrong, and already he was bending to his stride. Before he had taken half a dozen steps the head of the other man swung round hurriedly. Instantly the unknown quickened his pace. Before they had traveled a hundred yards, Hollister knew he was more expert in the use of the runners than the fugitive. Barring accidents he would catch him. The pursued man made for the rim of the valley. From time to time he turned without stopping to see whether he was losing ground. The distance between the two was lessening. Hollister knew it. Evidently the other knew it, too, for he tried desperately to increase his pace. The hundred yards had become seventy-five, fifty, twenty-five. They were out of the valley now, swinging toward the left where a patch of timber lay back of a clump of quaking asps. A pile of boulders were huddled beneath a rock-rim a stone’s throw to the right. The snow was falling more heavily now. It was plain that the fugitive was hoping to reach the timber and escape in the thickening storm. To prevent this, Hollister worked farther to the left. He came up quickly with the other and passed him fifteen yards or less away. A gun cracked. Hollister’s long stride did not slacken. He was keeping well away because he had known the other would be armed. The engineer had made a serious mistake in not stopping to get his revolver. Again the revolver sounded. The bullet flew harmlessly past. Tug had circled ahead of his prey and cut him off from the grove of quaking asps. He was relying on a piece of audacity to protect him from the armed man. The stranger would assume that he, too, was armed.