“That does seem wise,” Mr. Wright agreed, rising also. “Boys, let’s emphasize the Sky part of your order, and let the Squad side rest awhile. Barney wants to get back to the plant—he is the Manager, I meant to explain. He ought to be at the end of a telephone wire. Let’s say only this: There is a double mystery. First of all, valuable parts have been missed, from time to time, from the plant. That is a minor matter, at present, but your first puzzle is—where have the missing parts gone and who took them? But, as I said, that is a minor affair, because——”

“Somebody has tampered with some of the finished crates,” broke in Barney. “Why, and who—that’s the second puzzle!”

“Suppose you take that as enough for the present,” suggested Mr. Wright. He turned to Barney. “Now these three young lads are alert, obedient, and they will follow instructions to the letter, if you give orders,” he explained. “You have already seen how——”

“How quick they are in emergencies! Yes sirree! All right. I know I can depend on them. Sorry you can’t investigate in person, Mr. Wright—but maybe this way will work out best. Anyhow, nobody at the plant will get suspicious of these boys. They won’t have the brains of older men, like you and me, but they will have quick eyes and wide ears,” he laughed, and beckoned, “come on, lads.”

A little disappointed, feeling that there was more behind the mystery than Mr. Wright had disclosed, but accepting his “lead,” Bob, Al and Curt caught up their caps from the hall rack and followed Barney into the car.

As he drove toward the large manufacturing buildings, the administration offices and the assembling rooms, “dope” rooms and testing field that formed the Tredway Aircraft Corporation plant, Barney kept away from talk about the mysteries.

Instead, he questioned them about the plan for their new organization, suggested secret codes, urged them to elect a “Boss Pilot” and really fired their imaginations to such a point that when they came in sight of the aircraft plant they had almost forgotten their disappointment at not being taken fully into his confidence.

“Well,” he said, when they turned in at the gateway in the high board fence that kept curious wanderers out of the grounds, “here we are, Sky Squad—ready to begin to learn how a crate is started, what the design means, and why certain things have to be planned for—and then, what goes into construction and why, how she’s put together, and then, how to fly the finished crate.”

Sensing from his tone that he wanted them to concentrate, at least outwardly, on airplane construction and to let the other part of their activity be kept quiet, the three comrades agreed by assuming an interest that was by no means hard to pretend, when he took them into the offices, introduced them to some of the men working there, and explained that he was going to put them to work “to learn to build crates from the prop to the tail skid.” Barney, on the way, had learned their special interests. Therefore he put Bob into the engine assembling division where he could learn more about radial engines and the experiments being conducted with oil-burning types. Curt, who was methodical, cool and careful, was assigned to work, at least for awhile, in the wing assembling rooms. Al, being rather young for too much technical understanding, was assigned as helper to a “rigger,” who had been grumbling for some time at the laziness of his present assistant.

Everything was so new and so interesting that the trio forgot the seriousness with which Mr. Wright had assembled them that morning; but as they rode their bicycles toward home at lunch time, Bob imparted information that both startled them and turned their minds back to the serious business really underlying their work.