After an hour of straight driving on a deserted road, she became quite dexterous at operating the gears. When she felt entirely confident of her ability to handle the car in any emergency, the girls drove back into the city. They parted at the Brunner garage where Penny had left her own roadster. "Thanks for helping me select the car," Susan told her chum gratefully. "I didn't have much to do with it," Penny smiled. "But it's a fine looking automobile. I wish I had one half as nice." "I'll let you drive mine whenever you like," Susan offered generously. When Penny reached home it was nearly dinner time. Mrs. Gallup was busy in the immaculate green and white kitchen, frosting an angel food cake. "Any mail for me this afternoon?" Penny inquired, pausing to scrape up a generous spoonful of fudge from the frosting pan. "I declare, I've been too busy all day to even think of the mail." "I'll look." Penny went to the box at the front door. There were three letters. Two for Mr. Nichols and one for herself. The latter was addressed in pencil on a cheap yellow envelope. "Wonder who it's from?" she thought with interest. Quickly, she ripped open the envelope, glancing at the signature which had been signed at the bottom of the brief note. "Jerry Barrows!" she exclaimed. Eagerly she read the message. "Sorry I couldn't keep the appointment with Mr. Nichols," the boy had written. "Tell your father to be on guard. His life is in danger." CHAPTER V Penny Turns Sleuth Mr. Nichols did not have a great deal to say regarding the note which Penny read to him later that evening at the dinner table. "Don't let it worry you," he advised. "Just put it away for future reference and forget about it." "Future reference?" "Yes, it's always wise to keep such communications. One never knows when a sample of handwriting might prove useful." "I'm sure Jerry Barrows must have some good qualities or he'd never have sent the message. Don't you think so, Dad?" "Perhaps. It's obvious the boy was afraid to talk with me." "But why should he warn you that your life is in danger? Do you think he could know anything concerning the Molberg gang?" "It isn't likely, but he may have some underworld connection." "I'm getting more nervous every day," Penny declared. "I'll never feel very easy until all the members of that gang are captured." "It may be a more difficult task than I at first believed," her father remarked, frowning. "I know that Rap Molberg is hiding somewhere in the city but so far none of my investigators have been able to trace him." "Perhaps he's through causing trouble," Penny said hopefully. "He'll make enough when the time comes." "I've not heard of any automobile thefts or anything of the sort for several days." "That's just it. Things have been altogether too quiet. It's like a lull before the storm. A bad sign." Mr. Nichols abruptly left the table. He walked to the door, then came back.