Dave chuckled as the Colonel's remark came to his ears, but his heart pounded a little harder and the warm glow of pride rippled through his veins.

"Thanks, sir," he said. "And sorry that I exploded that way. But don't worry, I'll get us out of this little jam if it's the last thing I do."

"Well, see that it isn't, my good man!" Freddy Farmer grunted.

For the next few moments nobody said a word. All three of them leaned forward in their seats and strained their eyes at the darkness ahead and below. Dave's hands felt cold and clammy, and he could feel the little drops of sweat ooze out on his forehead and trickle down his face. For the last fifteen seconds or so he had spotted what he believed to be a mountain peak just ahead, and not more than a hundred feet below. He didn't say a word to the others. He kept his mouth shut and eased the plane a little to the left so as to be able to pass on by the peak with enough free air to spare between his right wing tip and the unseen trees or jagged rocks he knew must dot all sides of that peak. Once past it, he could start the engines again and climb for altitude. It was a cinch that the unknown attacker was cutting about in the black sky somewhere far behind him. But once he got beyond that peak he felt that his lead would be great enough for him to risk showing his exhaust plumes. As a matter of fact, though, it was quite possible that the unknown attacker was miles and miles behind. It was possible that the man had cut around to the east, believing that Dave wouldn't dare chance holding his westerly course with the mountains so close.

"Yeah, maybe!" he murmured. "But I'm going to make sure just the same!"

"What did you say, Dave?" Freddy Farmer cried out in a voice of alarm.

"I didn't say a thing," Dave grunted, and tightened his hold on the controls. "Just thinking a little out loud. Shut up, little man, or you'll make me rock the boat."

Freddy Farmer caught his breath as though he were about to speak. Instead, though, he said nothing. He simply leaned farther forward in his seat. Dave caught the movement out the corner of his eye, and grinned, tight-lipped. Freddy had sighted the mountain peak, but realized that he had seen it and was trying to slide by on the left. So the English youth had snapped his lips shut so as not to give Colonel Welsh a slight case of heart failure. Good old Freddy. Always knew when to open his mouth, and when to keep mum.

Perhaps it was six seconds, but it seemed like six thousand years to Dave before the slightly darker shadow that was the mountain peak slid past the tip of the right wing and disappeared behind. The instant it was gone from view he whipped on the switches, caught both engines, and fed them high test gas at full throttle. The roar of the engines breaking into life was a sound akin to worlds crashing into each other. Yet at the same time it was a welcome sound to Dave's ears, and to Freddy Farmer's too. But what filled their hearts with an even greater happiness was the Lockheed climbing upward to a safe altitude above the mountain range. The instant he was well clear, Dave swung the plane onto its westerly course again, and relaxed in the seat.

"Top-hole, Dave," Freddy Farmer said quietly. "A very pukka bit of flying, that."

"Thanks," Dave replied. "We got away with it okay. But I'd hate like heck to have to do it every day. You spotted that mountain peak, didn't you?"

"Quite," the English youth murmured. "But I thought it best to keep my mouth shut. Realized that you knew what you were doing. And besides, no sense in—"

"No sense in giving this old dodo grey hairs, eh?" Colonel Welsh spoke up with a chuckle. "Well, it was nice of both of you, but I saw it, too. The only reason I didn't speak, though, was because my tongue was frozen stiff. As you say, Dawson, I'd hate to have that sort of thing for a daily diet. Very sweet flying, though, very sweet."

"We could have made it sweeter if this plane had been armed," Dave grunted, and stared at the black sky ahead. "That tramp certainly had his nerve jumping on us. Wonder who the heck he could be. Sure you haven't any ideas, Colonel?"

There was a long minute of silence while the senior officer seemed to make up his mind.

"No, I'm afraid I haven't," he finally said slowly. "As you mentioned awhile back, there are probably plenty of birds who would like to see me out of the way. Somehow, though, I can't see them going about it in this manner. Their style is more along the line of pot shots from dark doorways. Or a bomb in my car, or tossed through my window. Frankly, I can't make head nor tail of this business tonight."

"Many chaps know you were headed west, sir?" Freddy Farmer asked quietly.

"What do you mean, many?" the Colonel replied sharply. "Did I broadcast it, you mean?"

"Hardly that, sir," Freddy chuckled. "I mean, did you tell many people that you were making this trip? Not that any of them are in the pay of Tokio or Berlin, sir, but it's possible that one of them might innocently enough mention the fact to somebody who was. You understand what I mean, sir?"

There was another moment of silence while the chief of U. S. Intelligence thought things over.

"I see what you mean, Farmer," he grunted presently. "No, I didn't tell anybody who didn't have the right to know. Fact is, the only ones I told were those three officers you met in my office. And if those three aren't one hundred per cent Americans, then I'm Adolf Hitler in the flesh."

"What about the other end?" Dawson asked.

"What other end?"

"San Diego," Dave said. "Is your man in charge there expecting you? Or are you just dropping in on a surprise visit?"

"No wonder you chaps always come out on top," Colonel Welsh said in a frank tone. "Once you get your teeth in something you keep at it until there's nothing left. Yes, I did wire my head agent in San Diego that I was coming west tonight. And—"

"And my first month's pay as a U. S. Naval Aviation Lieutenant says somebody read that wire!" Dawson cut in quickly.

"Hold it!" Colonel Welsh cried, and laughed shortly. "You're flying one wing low this time. I said in the wire that I was coming out, but I didn't say how, or what time I'd arrive. Afraid you're off on the wrong scent there, Dawson."

"Maybe, maybe not," Dave said doggedly. "But that chap didn't have a crack at us tonight just for gunnery practice. He was shooting for keeps. He knew darn well who was in this plane—and he was out to get us. He—"

Dave didn't finish. At that moment the right outboard engine of the Lockheed lost revs fast and began to sputter and clatter. Dave snapped his eyes at the dash dials, and sucked in his breath sharply as he saw the oil pressure needle sliding around the face of the dial toward the zero peg. However, even as he glanced at the needle, it stopped swinging back and promptly climbed upward again. The engine stopped sputtering and clattering, and once again sang its full throated song of power.

The tiny lump of ice remained in Dave's chest, however. He glanced sidewise at Freddy Farmer and saw the corners of the English youth's mouth tighten a bit.

"What the devil was that?" Colonel Welsh demanded in a sharp tone. "Something wrong with the engine?"

"Not now," Dave said with an easiness he didn't feel. "Guess it picked up a bit of ice but got rid of it in time. Anyway, she's back where she should be. As I was saying, that lad tonight was out for blood. So it must follow that somebody knew where you were going, when, and how. Don't you think so, sir?"

Dave spoke the words, but it was really just an effort to keep the conversation going. The lump of ice in his chest was hurting him again, and he was feeling far from calm and collected. The way the oil pressure of the right outboard engine had dropped told him that there was trouble ahead. Many people claim that the carburetor is the heart of an engine, and probably it is, if you want to look at it that way. However, countless hours in the air had proved to Dave that your real danger signal is when oil pressure starts dancing around. Engines can run, often for a long, long time, when the carburetor is out of whack and the engine is getting a bad feed. But let oil pressure go screwy and you'll have real trouble on your hands. There are no halfway measures about oil. It has to be right or your engine is worth no more than its weight in junk. Gasoline is food for an engine, but oil is its life blood. If it hasn't got the proper amount it dies, but definitely!

And so Dave spoke the words just to keep the conversation going and fixed his eyes on the instruments pertaining to the functioning of the right outboard engine. He hoped and prayed that the skipping had simply been just one of those things. But in his heart there was gnawing fear and dread. He feared that bullets from the guns of that unknown attacker had nicked one of the oil feed lines, and that continued vibration of the engine was slowly but surely shaking the feed line connection loose, or at least causing it to crack and buckle slowly, so that eventually the pressure set up in the line would be reduced to nil.

If it had been daylight, or if he had been sure of the terrain below, he would have landed and made sure what had happened. But a landing was too great a risk right now. His best bet was to keep going, nursing the right outboard engine as much as he could, and hoping and praying that it would continue to tick over and produce power.

"Yes, I guess your reasoning is sound enough," he heard the Colonel say. "It's rather hard to believe, though. I mean, why go about it in such a—well, in such a story book thriller style, you might say? I'm not going to San Diego on any vital mission. Fact is, I could make this trip tonight or next week, and it wouldn't make much difference. That's what makes it seem so—so utterly crazy."

There was a moment of silence, and then Dave laughed a trifle flat-toned.

"I don't mean to be conceited," he said. "But what you've just said, sir, doesn't make me feel so good. Or maybe it should make me feel important as heck. How about you, Freddy? Catch on?"

"I think so," the English youth replied. "But it's a bit—er, fantastic, you know. However, I would feel a bit better if we had been able to shoot the beggar down. Always did say night attacks weren't quite the sporting thing, you know."

"Not the sporting thing, huh?" Dave echoed with a snort. "Pal, that's only putting it by half. In my book they're plain murder."

"Of course, I'm only the passenger," Colonel Welsh spoke up sharply. "So don't mind me. However, I would like very much to know what the devil you two are jabbering about. What's it all about, anyway?"

"You tell him, Freddy," Dave said. "I—I feel too modest."

"Rubbish!" the English youth snapped. "You couldn't be if you tried. Besides, you brought it up."

"Listen, you lads!" the chief of U. S. Intelligence boomed in exasperation. "Have I got to use my authority as a Colonel? What in blue blazes are you two talking about?"

"The fantastic, sir," Dave said with a chuckle. "Yet, on the other hand, possibly the truth. Maybe the pilot of that plane didn't want Farmer and me to go aboard the Carrier Indian."

Colonel Welsh made a hissing sound as he sucked in his breath sharply.

"Great guns!" he gasped. And then in the same breath: "But that is impossible. Not even my three closest assistants knew that was to happen until I informed you. And we went from my office straight to Alexandria Field. No, you must be wrong, Dawson. Captains Lamb and Stacey, and Lieutenant Caldwell, wouldn't breath a word of that even though a gun were held at their hearts. That is fantastic!"

The two boys looked crestfallen.

"See, Freddy?" Dave cried, and jabbed an elbow in his pal's ribs. "You get the screwiest ideas. I never—!"

"None of that, funny boy!" the English youth barked back at him. "No, you don't, not by a jugful. You brought it up. I simply agreed with you, to be polite. You're quite right, Colonel. It's ridiculous. But when you get to know Dawson better, you'll understand how he's—"

The rest of what Freddy Farmer would have said to the Colonel stuck fast when only halfway up his throat. The right outboard engine had started kicking up again, but this time it was really doing it in earnest. The oil pressure needle went around to the zero peg in a single jump. And even as Dave grabbed for the throttle, the right outboard engine let out a grinding scream as though it were actually something human, and in mortal pain. It had run dry and was seizing up. Almost at the same instant, and as though in sympathy for its mechanical brother, the left outboard engine started falling off in revs at an alarming rate. Dave killed the right engine completely, shoved hard on the left rudder to check the plane yawing, and concentrated on keeping the left outboard engines alive as long as possible.

"That tears it!" he said between clenched teeth. "I was afraid that right engine had been nicked. Getting ready to drop a couple of those landing flares, Freddy. At least we can take a look at what it's like below."

"Take a look?" Colonel Welsh cried sharply. "You don't have to, boy! There are mountains down there. Get us as high as you can, and then we'll all bail out."

A hot wave of anger swept through Dawson, but he was able to choke the words back in time. Instead he turned to Freddy Farmer and nodded.

"Let a couple go, Freddy," he said quietly. "We're only losing a foot or two of altitude. We'll take a look first!"