Bob Houston, the youngest agent of the Federal Bureau of Investigation, stepped out of the Department of Justice Building and turned toward home, his heart beating faster than it had in months. It hardly seemed real but he was now a full-fledged agent in the greatest man hunting division in the Federal Government.Bob paused a moment at the curb. Another man who had emerged from the justice building joined him. It was his uncle, Merritt Hughes, one of the most famous detectives in the department. He put his arm around Bob's shoulders and shook him in a rough but friendly embrace.“Well, Bob, how does it feel to be a real federal agent?” he asked.It was a moment before Bob replied, and when he finally spoke the words came slowly.“I hardly know,” he confessed, “as yet it doesn't seem real, but there is one thing I do know—I'm going to work night and day to make a success of this new job.”“Don't worry about making a success,” advised his uncle. “You've got the stuff to make good or you wouldn't have been taken into the department.”“When do you think I'll get my first assignment on a new case?” asked Bob.“That's hard to say,” replied the famous detective, “but if I were you I'd go home now and get a good night's sleep. In this kind of a game you'd better sleep when you can.”“Then I'm headed for home now,” said Bob. “Good night, and thanks for all you've done for me.”With that the young federal agent strode off down the avenue, his lungs drinking in great gulps of the cool air of the fall night.Merritt Hughes stood on the curb of the justice building watching his nephew until Bob turned the corner a block away. Anyone noticing the federal agent would have seen a slight smile of pleasure on his lips and he might have guessed that Merritt Hughes was greatly pleased by the events which had happened in the preceding hours.As a matter of fact, Bob Houston, a plain clerk in the archives division of the War Department, temporarily a provisional federal agent, had been the key figure in preventing the theft of some of Uncle Sam's most valuable radio secrets.