Dave waited for the man to continue, and when he didn't he put another question to him.

"We start from scratch, sir, you mean?" he asked. "There isn't any kind of a clue for us to work on? You're stationing us aboard the Indian, of course?"

"That's right," the chief of U. S. Intelligence replied with a nod. "The Indian is shy two flying lieutenants, and you two are going to fill the vacancies. Matter of fact, the Indian is also shy two machinists' mates, and they'll be put aboard too before she weighs anchor sometime the day after tomorrow."

"Two of your men, sir?" Freddy Farmer spoke up, giving the Colonel a keen stare.

"Right," the senior officer said briskly. "But, I'm not going to tell you who they are, any more than I'm going to tell them who you are. That may sound strange, but it's been my experience that agents working in pairs accomplish more than agents working in a group. As officers you two will have the run of the ship, you might say. At the same time, though, you might tip your hand if you went poking around in the non-com and enlisted men's quarters. It works the other way around, too. So I'm planting men in both departments of the ship. You won't know who the other two are, and they won't know who you two are. But here's a very important point to remember. This Intelligence work I'm counting on your doing is, in a way, over and above the call of duty.

"I mean by that that you two will be aboard ship as flying lieutenants. That will be your main job, and you'll take orders from your Section Leader, or higher ranks, just as though we'd never had this talk at all. You'll have no special privileges any more than anybody else aboard ship will have. You won't because not a living soul aboard will know the real reason why you are there. Not even the Indian's captain will know. As they say in England, this is going to be a strictly hush-hush job. Yes, you'll be starting from scratch. All I can arrange is for you to be assigned to the Indian to fill the two flying officer vacancies. What happens after that is up to you. A tough one, eh?"

"The odds aren't so good," Dave said with a faint grin. "But I see your point, sir, and its advantage. If nobody knows why we're there, then there's no chance of the truth leaking out."

"I say, one point, though," Freddy Farmer spoke up with a worried expression on his face. "What about me? My accent, I mean. Won't it seem a bit odd for me to be put aboard an American aircraft carrier?"

"Not a bit, so stop worrying about that," Colonel Welsh said with a smile. "A month or two ago, yes, but not now. You have only to pick up the papers to see that both American and British airmen are being trained in this country. We're not keeping things separate any more. Take Java, for example. There are Yanks, British, and Dutch over there all fighting together, and under the Dutch Command. We're the United Nations now. And we'll become more so before this thing is over. No, Farmer, it won't seem odd at all for an English youth to have been trained in this country and be assigned aboard a U. S. Navy aircraft carrier for sea duty. True, you may get a bit of ribbing—about your English accent, and stuff. But I guess you can take that, eh?"

"Farmer has learned fast, sir," Dave said with a chuckle. "He can dish it right back with the best of them. Snappy come-backs are apple pie for him. I even have to bear down myself at times. Fact is, I wouldn't be surprised but that in six months or so you won't be able to tell him from a Yank."

"Goodness, no, if the Yank is you!" Freddy said with a groan.

Dave laughed and cocked an eye at Colonel Welsh.

"See what I mean, sir?" he grunted. "Right on top of the ball all the time. He's good!"

"Well, I don't think any of us have anything to worry about on that score," the Colonel said. "And I've a hunch, Farmer, that once your shipmates see you in the air they'll realize that how a chap speaks is pretty small potatoes, considering. Well, I guess that's all. You leave tonight for San Diego. There's a Navy plane out at Alexandria Field. You can take that. And there'll be a passenger on your trip west, if you don't mind."

"Glad to have company," Dave said. "Who is he, sir?"

"Me," Colonel Welsh said with a grin. "I've got some business out on the Coast. So I might as well hitch-hike on your plane. Oh! In case you're wondering, you'll be fitted with uniforms and gear before we leave. For this job you'll have the rank of lieutenants. That's below your R.A.F. Flight Lieutenant's rank. Our Navy Lieutenant is equal to your rank of Flying Officer. An R.A.F. Flight Lieutenant is equal to our Lieutenant Commander, or an Air Corps Captain. But I don't think it wise to put you aboard the Indian as Lieutenant Commanders. Fact is, too, the vacancies are for lieutenants. So I hope you don't mind, eh?"

"Not a bit, sir," Dave replied instantly, and laughed. "As a matter of fact, just a few minutes ago you told us that we weren't even R.A.F. any more, so any rank you give us is bound to be okay. But, speaking for both of us, what rank we hold doesn't mean a thing. If we can pull this thing off, it's okay by us if we go aboard the Indian as a couple of seamen, third class. But—well, there are a couple of questions I'd like to ask. Or are you in a hurry, sir?"

"No hurry except to nail that rat aboard the Indian before she gets into the Marshall Island attack," Colonel Welsh said bluntly. "No. For heaven's sake, go ahead and ask all the questions you want. I certainly don't want you to go into this thing not knowing everything you should, or at least everything I can possibly tell you. What's your first question?"

"Something I hope won't happen, but might," Dave said with a frown. "Supposing Farmer and I catch onto something—get a line on this rat, or rats—but really need help. Is there anyway we can contact the two mechanics you're putting aboard to help us?"

Colonel Welsh glanced at his three junior officers and smiled before he looked back at Dave.

"A good question, Dawson," he said. "I was going to tell you about that as we flew west tonight, but now that you've brought up the point, I might just as well do it now."

The chief of U. S. Intelligence paused long enough to pull open one of the countless drawers of the huge desk. When he took his hand out of the drawer, he held two pins. They were common ordinary looking pins save that the top was painted a bright orange. He gave a pin to each of the former R.A.F. aces.

"Many, many times my agents have worked on a case and didn't know who else was working with them," the Colonel began presently. "And often they got in tight corners and needed help badly. So—But hold it a minute. Let me mention something else right here. When I say tight corner, I don't mean that the agent is about to be caught, or about to be killed. I mean more than that! I mean when he gets in a spot where valuable information he has collected may be lost unless he gets help. Or when something is about to happen that will seriously harm his country unless he gets help. That sort of thing. Not the present or future welfare of the individual agent. You see what I mean?"

"Yes, sir," Dave replied, as his stomach suddenly felt a little hollow and empty, and his mouth went just a little bit dry. "Help to save your country, but not to save your own life, eh?"

"Exactly," the senior officer said, and nodded at the two orange-headed pins. "That pin is an agent's SOS sign when all else has failed. Keep that hidden on your person at all times. If the occasion ever does arise when you need help in the way I described, take that pin out and stick it in the right side of your shirt collar. If you're not wearing a shirt, then in the right side of the top of whatever garment you're wearing. In short, so that the orange head of this pin is nearest the right side of your face. If there is another agent near by, he will immediately make himself known by placing his pin in the exact place where you have put yours.

"Remember that. Don't forget it for an instant! If you need help, place this pin at the top of whatever garment you're wearing where it will be nearest the right side of your face. Even if you've only got a pair of pants on, put the pin in the right side of the pants at the very top. That clear?"

The two youths nodded. Then Freddy Farmer leaned forward a bit, and stared questioningly at the Colonel.

"Supposing, sir, you see the SOS pin on another chap," he said. "In the right place, of course. But supposing it may interrupt your own work to make yourself known to him. What then?"

"Establish your identity, regardless," Colonel Welsh replied bluntly. "That is a fixed rule in this department. And here is why. Because of what the SOS pin stands for: a last appeal for help when the welfare of the U. S. is in serious peril. I know what you're thinking. Your own case may be just as important as the agent's who is appealing for help. That is the chance we have to take, though. That is why the SOS pin can only be shown as a desperate last resort to forestall a great military and naval calamity. And to give you an idea of what I mean, I know of only two cases when the SOS pin was shown during the fifteen years I have been in this department. True, the coming of war will increase the possibility of the SOS pin being shown. But—well, that's for the future to bring to light. Now, let's have another question."

The Colonel glanced at Dawson, but it was Freddy Farmer who asked the question.

"If this skunk chap is still aboard the Indian, sir," he said slowly, "and if the aircraft carrier is to put to sea the day after tomorrow, what harm can be done by that chap? Do you believe that while at sea he will make some effort to get in touch with Japanese forces? And is our job to stop him from doing that?"

The senior officer thought over the answer to that for a moment, and scowled hard at the opposite wall.

"The best answer to that," he finally said, "is what I told you a moment ago. I mean that I can see that you are put aboard the Indian, but from then on you are absolutely on your own. Frankly, you will be doing no more than punching in the dark. I feel certain that the spy is still aboard, but I don't know for sure. If he is aboard, and the Indian puts to sea, the information he has collected may be just a beautiful white elephant on his hands. He may not be able to do a single thing about it until it is too late, and his information not be worth a darn. But the point is, we can't take chances on anything.

"You see, we have no idea whether our man is a seaman, a mechanic, or a flying officer. Suppose for a minute that he is a flying officer. Think of the opportunities he'd have to contact the Japs. On patrol he could sneak a message over the side that would drop down to be picked up by a Jap submarine. He might even break formation and scoot off to some point where he knows Japs naval vessels are on patrol, and contact them that way. He might not even return. No, Farmer, the fact that he goes to sea with the Indian doesn't make anything certain for us."

The senior officer paused, looked very unhappy, and sighed heavily.

"That is the rotten part of Intelligence work," he grunted presently. "Nine cases out of ten you have absolutely nothing to work on. You've just got to make blind stabs in the dark, and trust that you'll connect with something that will get you somewhere. The only suggestion I can give you is to keep your eyes and ears open every minute of the time—particularly your eyes. It seems certain that the murderer isn't going to keep his secret any longer than he has to. It's plain dynamite, and he knows it. He's going to try somehow to get that knowledge to the Japanese Fleet. If you can spot him and nail him, you will be everlastingly blessed by the Navy, from the President on down."

"Well, we'll do our best," Dave said grimly. "And I hope and pray it will be good enough."

"Amen, to that," Colonel Welsh said softly. Then, pushing up onto his feet, he said, "Well, we can start now by finding you two uniforms that don't look as if they were picked out in the dark. Then we'll go on out to Alexandria Field—and head west."