And now Tom’s heart rose up in his throat! Was that a shadow that he saw just behind the standing horses? How could it be, he thought; for it was moving. Pshaw! Maybe a shadow from a swaying bough. But say, there was no wind! How could a bough sway? A powerful feeling swept over him that danger, fearful danger, was close at hand. He clutched his rifle tightly, as the first slight trembling of his hands passed away. He was now cool and steady. Nothing happened, however. After a moment or two, the boy took a step forward, but he was yet hidden among the trunks of the willows. There had been no sound as yet from the horses, but now one of them stamped uneasily and then shied slightly to one side. Tom thought that he heard light steps, so light as to be almost inaudible. And now he heard them again. There was danger. Real danger. It was not mere fancy. He bounded forward and a shadow darted from behind the horse, the shadow of a feathered Indian. The warrior with a thrust of his knife cut the lariat of the horse, struck him on the flank, and gave voice to a shrill, wolfish howl. Tom threw his rifle to his shoulder and fired at the same instant. “Up! up!” he cried. “Indians!” As he paused to reload his gun, he saw that his hastily fired bullet had missed the savage, who now scurried off to the west. The fleeing brave could clearly be seen in the moonlight. The boy could make out that he was fully armed and in all the panoply of war-paint. Then, as he looked more sharply, he was fairly agape with amazement. “Prairie Wolf!” he exclaimed; and sent another bullet whistling through the night air; but there was only a low, derisive whoop, as the shadow faded like a phantom into the nearby thickets. Jim Martin rushed down from the northern arc of the circle, Bill Brown was out of his blanket in a moment, thoroughly alert and awake; and Lieutenant Clark and several of the troopers, together with Ben Gordon and Bright Star, were not far behind. “Watch the horses!” yelled Bill loudly. “Ther gittin’ ready to stampede!” Tom and Jim jumped forward and seized the lariats of two of the nervous beasts. The rest of the party likewise hurled themselves into the milling group. Everybody seemed to be all hands, grasping as many lariats as possible. For a moment or two the frightened beasts reared and struggled, but soon they subsided into silence; and, although they stood quivering, they made no further effort to break loose. “You saved us, Tom, my boy,” said Bill Brown warmly. “The Sacs, the skulkin’ varmints, was bound to run off our horses, but you saw ’em in the nick o’ time.” “Brave lad,” praised the Lieutenant. “If the red snakes had stampeded our mounts, we wouldn’t have been much better off than sailors in the middle of the ocean without a boat.” Tom Gordon flushed with pride in the darkness; and his heart was glad that he had passed his first test in the hard, cruel school of Indian warfare.