For another twenty-four hours the dam was watched for indications of weakness, but none developed. Now that the big work was completed Tom and Hippy journeyed to the wrecked dam of the timber-pirates. They examined what was left of it with great care. Finishing their investigation, the two men looked at each other with eyes full of meaning. "Well, what do you think of it?" questioned Hippy. "I think, Hip, that it was something more than structural weakness that caused this dam to go out," answered Tom. "What do you think did it--I mean how was it done?" wondered Lieutenant Wingate. "Dynamite!" The word came out with explosive force. "The pirates don't like our presence here, so thought they would put us out of business. They didn't know us, did they, Hippy?" "No. I wonder what they will think now--or do?" "Nothing in the way of damaging our property, for we shall have our works watched after this. They might blow the upper dam, of course, but there are no logs being held there and the water would simply flow over our construction without doing damage. We must tell Willy what we suspect and assign him to guard duty. An Indian can sleep and yet be on watch." "Like Hindenburg, who always sleeps with one ear awake," suggested Hippy. "But never hears anything with it," laughed Tom. "We'll see." Later in the day when Tom spoke confidentially with the Indian about what the Overlanders suspected, Willy evinced no surprise. He nodded in agreement with Tom that the new dam must be guarded. It was. Willy slept near it in a lean-to down near the river. For several nights nothing occurred to indicate that there was anyone within miles of the camp. By day Willy hunted, often not coming in until after dark. It was on a Saturday night, however, that Willy failed to reach camp until nearly midnight. On his back he bore the carcass of a young deer that he had shot and dressed miles from the Overland headquarters on the bank of the Little Big Branch. He was nearly in when suddenly he raised his body to an erect position, listened for a few seconds, then dropped his burden and sprinted for home. The Overlanders long since had turned in and the lumberjacks were in their bunks, comfortable, and as happy as a lumberjack permits himself to be, when suddenly their bunk-house seemed to be lifted free of the ground. It swayed and trembled as a terrific crash rent the air. The tepee toppled over at the same instant, leaving the Overland girls lying in the open. Tom and Hippy, at the time asleep in their lean-to, which was a few yards nearer the river, never were able to decide whether they had been hurled from their beds or had leaped out before they were fully awake. At least, they found themselves outdoors, and some yards from the lean-to. "For the love of Mike, what now?" gasped Hippy. Hindenburg was running about in circles, uttering dismal howls, and the pet bear was scrambling for the top of the highest tree in his vicinity.