A dark cloud that had been creeping across the sky began to obscure the moon, and gradually the vivid illumination that bathed the hillside gave way to gloom and darkness. The cloud hid the moon completely. "Now's our chance!" whispered Frank, to his brother. "Head toward the willow tree." He scrambled to his feet and together the boys raced down the slope toward the willow tree back of the mill. Their feet made no sound in the deep grass. They were taking a desperate chance, they knew, for, in spite of the cloud that had fallen across the moon, Markel might be able to see them. But Markel had just emerged from the mill and his eyes were not yet accustomed to the gloom. As the boys reached the shelter of the willow tree, the moon emerged from behind the cloud and slowly the hillside was again bathed in radiance. Panting, the boys halted beneath the tree and looked back. They could see the dark figure of Markel as he cut across the slope in a diagonal direction and they watched as he drew near the place where they had been lying. They saw him stop, kick at something in the grass, then they heard him mutter as he turned away. "Well, what was it?" called the other man from the doorway of the mill. "It was a log all right," admitted Markel in a disgruntled tone. "But I could have sworn I saw it move a while ago." "Better get your eyes tested." To this pleasantry Markel made no reply, but trudged on down the slope until he again reached the mill. The boys pressed close to the willow tree. "You may think I'm being too careful," they heard Markel saying. "But we've got good reason to be careful. You know what'll happen to the whole crowd of us if we're caught." "Sure. About twenty years in the pen. But we're not going to be caught I tell you." "Don't be too sure. We can't afford to take chances, anyway. I'd rather keep my eyes open and get fooled by a few logs on the hillside than feel too safe and spend the rest of my life behind the bars." "I guess you're right. Anyway, everything is all right to-night." "I'm going to take a trip around the mill, anyhow." "Your nerves must be jumpy." "They are," snapped Markel. "My nerves are always jumpy when I think I see something moving down toward here from the woods--and I don't care whether that was a log or not, I saw something move." "Oh, probably a sheep or a cow that strayed from one of the farms. Or even a dog." "Yes, it might have been a dog," Markel admitted. "We'd better get to work. Dock is waiting for us." "I'm going to walk around the mill once, anyway." "Go ahead. Go ahead, then," said the other man. "I'll be inside with Dock." The boys heard heavy footsteps as Markel left the doorway, and then they saw his dark figure in the moonlight as he came around the side of the mill.