"I must go downtown again this evening, Penny," he said regretfully. "I'll leave the telephone number of my new office in the event you should need to reach me. It isn't listed in the 'phone book,' of course." "Your new office?" Penny demanded. "What became of your old one, may I ask?" "It's still there," Mr. Nichols smiled. "Miss Arrow has assumed charge, and I've taken up temporary quarters on the tenth floor of the Atler building." "Isn't that almost directly across from the Brunner garage?" "Yes, it's located in the downtown theater district. The bulk of the auto accessory thefts have taken place in this relatively small area. From the window of my new office I secure a bird's eye view of all that goes on in nearby streets." "Surely you don't expect to catch the thieves in the act of stealing automobile wheels!" Penny marveled. "It will be the surest way of gaining a conviction. If a professional crook isn't captured at the scene of his crime, he usually is clever enough to cover his tracks completely. An amateur is seldom so skillful in obliterating clues." "May I visit this new office of yours?" Penny asked. "Yes, if you use discretion and don't come too often. I have taken the office under an assumed name--John Bradford. I shouldn't care to have my real name known for awhile." "I'll be very discreet if I come," Penny promised. Her father turned to leave. "It must be dull for you here alone at night," he said apologetically. "Why don't you take Susan to a picture show?" "I think I'll do that," Penny agreed. After Mr. Nichols had left the house, she telephoned Susan. Mrs. Altman answered the call, informing her that her daughter was spending the evening at the home of an aunt. "I may as well go to the show alone," Penny decided. One of her favorite movie stars was showing at a neighborhood theater only a few blocks from the Nichols home. Penny walked the short distance. She thoroughly enjoyed the picture, remaining to see part of it twice. It was a little after nine o'clock when she left the theater. Recalling that Mrs. Gallup had requested her to bring home a pint of ice cream, she crossed the street to the nearest drug store. While she was waiting to be served, a man in grimy workman's clothes slouched into the store. He pretended to interest himself in a cigarette slot machine, but Penny noticed that he darted furtive glances at the waiting customers. Something about the man's appearance struck Penny as peculiar. She conceded that he looked like a day laborer yet his actions and mannerisms were not in keeping. "I've seen him before," she thought. Suddenly the picture of Rap Molberg flashed into her mind. Yet as she scrutinized the man a second time she could see only a slight resemblance to the photo her father had shown her.