"We wouldn't dare to light it, Sam," answered Tom. "Let us crawl up close to the building. Maybe we can find out something more about the men. They may be some good for nothing fellows from the village." As there seemed nothing else to do, this advice was followed, and soon the boys were at one of the broken out windows of the mill. They listened and looked inside, but saw and heard nothing. "They are not here," whispered Sam, disappointedly. "They are not far off," answered his big brother confidently. "Look!" came from Tom. "A light!" He pointed through the window to the flooring inside. From between the loose boards shone several streaks of light. As the boys gazed the light vanished and all was as dark as before. "They are in the lower room, the one where the water wheel used to be," whispered Tom. "Maybe that is where they have been hanging out." "Come after me--but don't make any noise," said Dick, cautiously. "If they have gone into the second room down there maybe we can make them prisoners!" "That's the idea!" cried Sam. "Just the thing!" "Hush, Sam, or you'll spoil all." Scarcely daring to breathe, now that they knew the strange men were so close, the three Rover boys walked to the open doorway of the old mill and went inside. Dick led the way and crossed to where an enclosed stairs ran to the floor below. On tiptoes he went down, not trusting a step until he was sure of his footing. It was well he did this, for two of the steps were entirely rotted away, and he had to warn his brothers, otherwise one or another might have had a fall. Standing in the wheel room of the old mill the boys saw another streak of light, coming from the room which Dick had suggested. The door to this was closed, a bolt on the inner side holding it in place. There was another bolt on the outside, which Dick remembered having seen on a previous visit. "We can lock them in if we wish," he whispered. "Do it," answered his brothers promptly. The bolt was large and old fashioned, and Dick had considerable trouble in moving it into its socket. It made a rasping sound, but this was not noticed by the two men, who were conversing earnestly. "Well, we made a mess of it," growled the man called Shelley. "So we did. But I didn't think that hired man would wake up. Neither of us made a bit of noise. He must be a light sleeper." "I only hope they think we were after chickens, Cuffer. If they knew the truth--" The man named Shelley broke off with a coarse laugh. "Well, we got chickens the other night, didn't we?" and now the man called Cuffer laughed also. "But say, this is getting serious," he went on presently. "Merrick expects us to do this job for him and do it quick, and he won't like it at all when he finds out how we have missed it." "We can't do the impossible. Those Rovers are too wide awake for us."