She drove the sedan into the dark garage. As she was preparing to close the heavy double doors she thought she heard a step on the gravel path. "Is that you, Mrs. Gallup?" she called. There was no answer. "I _was_ right," Susan whispered tensely. "Someone is prowling about the grounds." "There's no one about," Penny maintained after peering carefully around. "Probably I imagined that I heard footsteps. Come on, let's go to the house." It was reassuring to see a light burning in the kitchen. The window shades had not been drawn and from the outside, Mrs. Gallup could be observed washing dishes. As the girls came in she greeted them in obvious relief. "I'm so glad you're back, Penny. I was beginning to be afraid that something had happened to you." "Quite a bit did happen," Penny laughed. "By the way, you haven't seen anyone prowling about the yard this evening, have you?" "Why, no, I've been so busy that I've scarcely glanced out the window. Early this afternoon a tramp stopped at the door for food. After I gave him a sandwich he went off. I hope he hasn't come back to make trouble." "Oh, no," Penny assured her quickly, "I'm sure there's no need for alarm." "Then why did you ask?" Penny was forced to relate what the policeman had told her, although she realized that the warning would worry the housekeeper. "Dear me, I don't feel safe with your father gone. To think that so much has been going on around here and I didn't know a thing about it! Why, I haven't even locked the doors!" "I doubt that it will be necessary now," Penny said, peering into the refrigerator to see what she could find for a belated supper. "Dad will soon be home anyway." "I'm going to lock all the doors and windows this minute," Mrs. Gallup insisted firmly. "With so much silverware in the house, it isn't wise to take any chance." Lowering the window blinds in the dining room, the housekeeper went directly to the buffet, removing a quantity of choice silverware which had been in the Nichols family for several generations. Leaving the girls to forage their own supper, she carried the box upstairs, intending to lock it in her own bureau drawer. Returning again to the lower floor she scurried about closing doors and slamming down windows. "Since she's bent upon doing such a thorough job, I suppose I should help," Penny remarked to her chum. "Finish your supper while I lock the back door." "Don't forget to set out the milk bottle before you barricade us in," Susan laughed. Penny picked the bottle up from the kitchen table and crossed the porch to place it on the step. It took her so long outside that Susan came to the door to learn what detained her. She was astonished to behold Penny standing as rigid as a statue, her eyes riveted upon the garage door. "What's wrong?" Susan inquired. "Didn't I close that door when I put the car away?" Penny demanded in a low tone. "Why, yes, I'm sure you did. The wind must have blown it open."