engineers.”

“Oh, I didn’t mean that you were careless, Bob,” smiled the Department of Justice agent. “I only meant that if you knew when radio secrets were going through you could use additional care and set up extra precautions.”

“You must be afraid something is going to be stolen.”

“That’s exactly what is troubling me,” confessed his uncle, “and I’m afraid that unknowingly you may be involved. I don’t want you to get caught in a trap if I can help it. That’s why I stopped here tonight. I wanted to have this talk with you, to warn you that there have been important discoveries by the engineers and that they may be through in a few days. From now on watch every single document that is sent through your hands. Don’t let it out of your sight from the moment it is delivered to you until you have filed it and placed it properly in the vaults. Understand?”

Bob, his face grave, nodded. “I’ll see that nothing like that happens. But who could be after these new plans?”

Merritt Hughes shrugged his shoulders.

“Bob, if I could answer that question this problem would be comparatively simple. The answer may be right here in this department; again it may be some outside force that we can only guess at.”

“Are you working alone on this case?” Bob continued.

A shadow of a frown passed over Merritt Hughes’ face.

“I wish I were; I’d feel more sure of my ground.”

“That means Condon Adams is also on the job,” put in Bob, for he knew of the sharp feeling between his uncle and Adams, another ace operative of the bureau of investigation. They had been together on several cases and at every opportunity Adams had tried to obtain all of the credit for the successful outcome of their efforts. He was both unpleasant and ruthless, but he had a faculty of getting results, and Bob knew that for this reason alone he was able to retain his position.

The fact that Condon Adams was on the case placed a different light on it for Bob, for Adams had a nephew, Tully Ross, who was in the archives division of the department with Bob. There was nothing in common between the two young men. Tully was short of stature, with a thick chest and short, powerful arms. His eyebrows were dark and heavy, set close above his rather small eyes, and his whole face reflected an innate cruelty that Bob knew must exist. If Condon Adams was also on the case, it meant that Tully Ross would be doing his best to help his uncle for like Bob, Tully was intent upon getting into the bureau of investigation.

Bob’s lips snapped into a thin, firm line. All right, if that was the way it was to be, he’d see that Tully had a good fight.

Merritt Hughes smiled a little grimly.

“Thinking about Tully Ross?” he asked.

Bob nodded.

“Then you know what we’re up against. It’s two against two and if you and I win I’m sure that I can get you into the bureau. If we don’t, then Tully may go up. What do you say?”

“I say that we’re going to win,” replied Bob, and there was stern determination in his words.

“That’s the way to feel. Keep up that kind of spirit and you’ll get in the bureau before you know it. In the meantime, don’t let any tricks get away from you in this routine. Watch every document that comes into your hands and let me know at the slightest unusual happening in this division.”

“I’ll even put eyes in the back of my head,” grinned Bob as his uncle stood up and donned his topcoat.

“How long will you work tonight?” asked Merritt Hughes as he opened the door which gave access to the hallway.

“Probably two hours; maybe even three.”

“Watch yourself. Goodnight.”

Then he was gone and Bob was alone in the high-vaulted room where the rays from the light on his desk failed to penetrate into the deep shadows and a strange feeling of premonition crept over him. For a moment he felt that someone was watching him and to dispel this feeling he turned on the glaring top lights.

The room was empty!

Chapter III
BOB HAS A VISITOR
★

Bob turned off the top lights and returned to his desk, which was one of half a dozen in the long and rather narrow room at one corner of the building.

As he sat down he could hear the beat of the rain against the window and looking out could see, through the curtain of water, the dimmed lights of the sprawling city. On a clear night the view was awe-inspiring, but on this night his only thought was to complete his work and to return to the warmth and comfort of his own room.

Bob delved into the pile of papers which had accumulated in the wire basket on his desk. They must be filed and the proper notations made. There was nothing of especial importance, or he would not have been working alone for it was a rule of the division that when documents of great importance were to be filed, at least two clerks and usually the chief of the division must be on hand. Sometimes even armed guards came in while the filing was taking place for some of the secrets in the great vaults across the corridor were worth millions to unscrupulous men and to other powers.

But until tonight, until his uncle’s words had aroused him, Bob had felt his own work was rather commonplace. There was nothing in his life which compared with the excitement and the almost daily daring of the men in the bureau of investigation of the Department of Justice.

The hours were rather long, the work was routine and his companions, though pleasant, were satisfied with their own careers. They were not looking ahead and dreaming of the day when they might wear one of the little badges which identified a Department of Justice agent.

Then Bob realized that he must stop his day dreaming. Or was it day dreaming after all? His uncle had said that there was now a possibility that he might join the department. But this was no time to ponder about that. He could think of his future when he returned to his room.

Bob went to a filing case which was along the inside wall of the room and extracted a folder. Taking it back to his desk he started making entries of the papers which were on his desk. He worked slowly but thoroughly, and his handwriting was clear and definite.

Others might be faster than Bob in the filing work in the division, but there were none more accurate and when his work was done the chief of the division always knew that the task was well cared for.

Bob worked for more than an hour, stopping only once or twice to straighten up in his chair, for it was tiring work going back to the desk after a full day of the same type of work.

When the file was complete, he returned it to the case along the wall and sorted the papers which remained on his desk. They belonged in four different files and he drew these from the cases and placed them in a row atop his desk.

The air in the room seemed stuffy and Bob walked to one of the windows and opened it several inches—just enough to let in fresh air, yet not far enough for the sharp wind to blow rain into the room. Far below him a car horn shrieked as an unwary pedestrian tried to beat a stop light.

Bob went back to his desk. Another hour and his work would be done. He picked up his pen and resumed the task.

Bob later recalled that he had heard a clock boom out the hour of nine and it must have been nearly half an hour later when the door which led to the corridor