Quickly and silently they went to the storeroom. They were not disturbed, for there were several class dinners on that night, and most of the occupants of Wright Hall were out. Andy and Dunk intended going later. They rummaged in the closet and, when about to give up, not having found what they sought, Andy unearthed a pair of rubbers. "These might be what the fellow wore," said Dunk, as he looked at them. "He could easily have slipped them off. See if there are any marks inside." Andy looked and uttered a startled cry. For there, on the inner canvas of the rubber, printed in ink, were the initials "M. G." "They're his, all right!" spoke Andy, in a low tone. "Then he's the quadrangle thief," went on Dunk. "Come on back to our room, and we'll talk this over. Something's has got to be done." "That's right," agreed Andy. "But what?" "We must set a trap," suggested Dunk. "A trap?" "Yes, do something to catch this mean thief--Mortimer or whoever he is--in the act." "Hadn't we better tell the Dean--or someone." "No," said Dunk, after thinking over the matter. "Let's see if we can't do this on our own hook. Then if we make a mistake we won't be laughed at." "But when can we do it?" Andy asked. "This very night. It couldn't happen better. Nearly all the fellows will be out of Wright Hall in a little while. We're booked to go, and Mortimer knows it, for I was making arrangements with Bert Foley about our seats, and Mortimer was standing near me. He came to borrow ten dollars, but I didn't let him have it. So he will be sure to figure that we'll be out to-night." "But how do you know he'll come to our room?" "I don't know it. I've got to take a chance there. But we can hide down in the lower corridor, and watch to see if he comes in this dormitory. If he does, knowing that 'most all the fellows are out, it will look suspicious. We can watch for him to go out and then tackle him. If he has the goods on him the jig is up." "Well, I guess that is a good plan," agreed Andy. "I hate to have to do it, but we owe it to ourselves, to the college and to poor Link to discover this thief. I only hope it doesn't prove to be Mortimer, but it looks very bad for him." "We can go farther than that," went on Dunk. "We can leave some marked money on our table, leave our door open and see what happens." "It sounds sort of mean," spoke Andy, doubtfully; "but I suppose if we have to have a trap that would be the best way to do it." "Then let's get busy," suggested Dunk. "He may not come to-night after all. We may have to watch for several nights. Meanwhile we'd better telephone the lawyer that we're on a new lead." This was done, and the man in charge of Link's case agreed to see Andy and Dunk early the next day to learn what success they had. Then the trap was laid. The two who were doing this, not so much to prove Mortimer guilty as to free Link and others upon whom suspicion had fallen, went about their work.