had bagged his!"

His wondering eyes sought the colonel's lean face. Lance expected to see it express amazement, incredulity. It didn't, though. He laughed!

hile Lance gaped, the older man went to the delicate machinery of the radiophone in one corner of the trim office. He clasped the earphones over his head, and spoke into the mike: "Headquarters, Air Force, Washington, Douglas, Base 5, speaking."

A tense moment passed while his radio call was put through. Presently a green light flashed on the board. Douglas said swiftly: "Headquarters? Base 5, Colonel Douglas. Tanks massed around Hill 333; enemy evidently contemplates full attack on corresponding sector of our line. They know a scout of ours observed it, however; perhaps that will induce them to change their plans. This next is extremely important: The first step of the Torpedo Plan has been successful!"

For awhile he listened intently, replying with short-clipped affirmatives. Then he hung the headphones up and turned to the bewildered Lance. Colonel Douglas laughed again and rubbed his hands exultantly.

"What the hell—" Lance began. The other pulled out a drawer of his desk and took from it a small placard.

"Do you recognize the photo?" he asked smilingly.

Lance looked at it. It was the picture of a man in the uniform of a captain of the Air Force, a row of battle ribbons on his straight, khaki-clad chest. But it was the figure's face that Lance stared at.

"Sure," he said finally. "It's a picture of Praed. But what—"

"Not Praed," corrected the colonel. "Not Praed. Captain Basil Hay."

PART III

ood Lord!" Lance exclaimed without knowing he did so. Praed—Hay! The same man! Then that was the secret; that explained things! Hay, the hero of the force!

"You're entitled to a few explanations," Douglas said. "I'll give you the core of the whole scheme. There's no need to tell you that it must be guarded with your life." He drew his chair closer to Lance's.

"Yes, it's true. The man you knew as Praed in reality is Captain Hay. You see, Lance, headquarters was taking no chances with what I just called the Torpedo Plan. Every move had to be conducted with the utmost secrecy. Had to be! For the Torpedo Plan is, in some ways, America's last hope.

"Our base, No. 5, was chosen as the center of activity, the base from which the steps paving the way for the plan would be taken. The two best pilots in the service were needed. You and Hay were chosen.

"It was decided it would be best to mask Hay's real identity. So, officially, he was sent to the hospital; in reality he came here, under the name of Praed. Why? Because there's a spy somewhere—we don't seem to be able to track him; he's infernally clever—and if the famous Captain Hay was switched to Base 5, putting the two best pilots in the service together, that spy'd know something was in the air. Understand?"

Lance nodded dumbly. A great light was beginning to shower him.

"To more completely mask our true purpose," the colonel continued, "Hay was instructed to make it appear as if he were a spy. And it was a damned hard job! The real spy, whoever he is, and wherever he is, would thus be additionally fooled; for all he'd know, the Slavs might have sent another over to back him up. That's why Hay never shot down an enemy plane. Says something about his skill as a pilot, doesn't it? Never able to defend himself, save by maneuvering. He's a great flyer!"

Lance could only nod dumbly again.

"After a couple of weeks at this base," Douglas went on, "Hay was to cross the lines one night with you accompanying him. You, unintentionally, would thus occupy the enemy planes while Hay attended to the real business of the evening. And you did splendidly!"

"The real business?" Lance questioned. "What the devil was that? I thought the real business was to get the dope on Hill 333."

"So it was—partially. But also to take the first step of the Torpedo Plan, which was for Hay to switch over to a Slav plane."

"What?"

he colonel repeated his statement, somewhat dryly. Lance's square jaw dropped abruptly. "But—but—" he exclaimed, "how the devil could he do that?"

Colonel Douglas grinned.

"By a very neat contraption from the brain of one of our most valuable scientists," he explained. "Hay's scout was specially fitted up before you left; while you were sleeping, in fact. Two experts from Washington arrived with that batch of new recruits this afternoon. A tiny sliding door was cut in the fuselage of the scout and a sort of folding ladder put inside. It was motivated by some rather complex spring-work; but the really ingenious thing about it was the powerful electro-magnet at its base.

"It's rather over my head," he smiled. "I'm a plain fighting man, and sometimes it seems that scientists and not fighting men are going to win this war.... But, at any rate, it worked like this:

"Hay lures, or maneuvers, a Slav plane away from its fellows, and while you're down below entertaining the others, flies wing to wing with it. He touches the spring of his ladder and it shoots out, powerfully magnetized, and clamps onto the steel fuselage of the Slav. The automatic control keeps Hay's scout steady, and the ladder is so highly attractive that the Slav simply can't get away. Hay crosses the gulf, taking with him the cord which controls the electro-magnet. He forces his way into the Slav, shoots down its pilot, releases the pull of the magnet, and—there you are! Our best pilot in possession of a Slav plane, and clad in a Slav officer's uniform! Do you get the idea now?"

Lance strove for appropriate words. "Gee!" he spluttered. "It's—it's wonderful! And to think I tried to start a fight with Hay! I wish I'd known before. But I suppose," he added, "it was best to let not even me in on it, to keep it absolutely secret."

"Exactly!"

"And now what's Hay's mission?" Lance asked eagerly.

olonel Douglas' face became sober. "A damnably dangerous one, and a mighty desperate one. As I said, the Torpedo Plan, which Hay is striving to carry out, seems to be America's last chance. We're holding the United Slavs, but only just. We simply can't break their line or make any headway against them; and when they do unleash their big push, there's nothing to stop them! So we're gambling everything on this slim hope.

"American science," he continued, "has perfected a weapon which is called the 'flying torpedo.' It's a ghastly thing, too. Damn it, I actually feel sorry for the poor devils it bursts on! It's a sort of riposte to their disintegrating flame.

"Picture a huge tanklike affair of steel, one hundred feet long. Picture a few dozen of them! Picture them crammed to overflowing with tons of glyco-scarzite, the most destructive explosive the mind of man has yet conceived. An explosive that can't be hurled in a shell and can't be dropped in a bomb from a plane. A pound or so of it, man, lays waste a square mile of anything! Even our scientists are a bit afraid of it. They've been trying to think up a way of unleashing it at the Slavs. And these flying torpedoes seem to be the answer.

"The torpedoes are purely mechanical.