They were being swept closer to the rapids every moment. There were a number of rocks rising above the surface of the river just a few feet ahead, and beyond that was a smooth, deep, swiftly flowing sheet of water that swept past the willows at the bend and ended in a quarter of a mile of rough, turbulent water, rapids and falls. "I'm going to help him!" exclaimed Frank, suddenly. He stopped on the bank and flung off his coat, then started to untie his shoelaces in order to kick his light shoes aside. But in the meantime Joe had managed to catch at a projecting rock with his free hand, so Chet put a restraining hand on Frank's arm. For a moment it seemed that the current would make Joe lose his grip, but he clung to the rock and drew himself closer until he had wrapped his arm about it. The rest of the rock was wide and flat and lay just a few inches beneath the surface. Slowly, Joe clambered on to this precarious refuge, dragging the half-conscious boy with him. The rock was big enough to provide foot-hold for them both. The boy was unable to help himself, as he was limp and weak from his experience. Just as he was almost on the rock Joe lost his grip on the lad's collar for a second, and the current whirled him to one side. The lad toppled backward, striking his head on the rock, but Joe made a frantic grab for him, at imminent risk of precipitating himself into the water again. His fingers closed about the back of the lad's shirt and he managed to haul the boy to safety once more. But the blow had rendered the lad unconscious. He lay limply on the flat rock, with the water breaking about his body, while Joe, his clothes drenched, clung to him. "Get help! Get a rope!" Joe shouted, to his companions on the bank. Frank and Chet lost no time. They fled back toward the old mill. The affair in the river had passed unnoticed by the millers, and when Chet and Frank rushed up to the front door they found no one in sight. "I'm going inside," declared Frank. "We'll have to get a rope or they'll be swept off that rock in no time." The door was closed, but he pushed it open and entered the dim interior of the mill. But hardly had he stepped inside, with Chet at his heels, than he ran into the arms of one of the men whom he had seen outside the doorway some time previously. "Hi, what do you want?" demanded the man angrily. He seized Frank by the shoulders and tried to push him back, out of the building. At the same time the other man came running out of a near-by door. "What's going on here?" he shouted wrathfully. "What's all this about? Get out of here, you boys!" The sound of voices evidently attracted the attention of a third man, for he, too, came running out of the shadows, carrying a heavy club, which he brandished threateningly. "What do you want here?" he shouted excitedly. He was short and broad-shouldered, with a dirty kerchief knotted about his neck.