With her twin engines thundering out their duet of mighty power, the American built Consolidated "Catalina" flying boat patrolled back and forth over the convoy of fifteen merchant ships plowing through the Atlantic swells toward the southwest coast of England. At the controls sat Dave Dawson, and at his side in the co-pilot and navigator's seat was Freddy Farmer. Aft at their respective stations were the three other members of the plane's crew. For seven long hours the flying boat had been escorting the convoy through dangerous waters. And every instant of that time five pairs of R.A.F. eyes had been searching the waters below for signs of a lurking group of Nazi "steel fish," and scanning the heavens for the first glimpse of a Nazi air raider winging out from its base in occupied France.

Nine solid hours of being constantly on the alert, and not so much as a single floating hunk of wood sighted. It was as though the Germans had no idea that valuable cargoes of war material were headed for England. Or else the presence of the Catalina flying boat and the small but heavily armed "Corvette" escort freighter leading the convoy made them decide to leave it alone. At any rate the merchant ships had not received a single scare, and soon they would be through the danger zone and unloading their war stuffs at England's docks.

Taking one hand from the controls, Dave dug knuckles into his tired eyes and sighed heavily.

"If this is the British idea of a joke," he growled, "all that I can say is that it smells out loud."

"Meaning what?" Freddy asked and made a few final marks on his navigation charts. "Mad because all those ships down there are going to get through safely?"

"Nuts, of course not!" Dave snapped and gave him a scornful side glance. "And you know darn well what I mean."

"That's true, I do," Freddy said and scowled out over the nose of the flying boat's hull. "Certainly is funny. Do you think by chance that something's gone haywire?"

"All I know is that I'm getting close to going haywire!" Dave replied savagely. "For two days now, we've been attached to Seventy-Four Squadron of the Coastal Command, and what have we done? Nothing but toot these big babies out over the Atlantic, pick up a merchant convoy, and toot back with them. Not a sign of a U-boat, not a sign of a Nazi plane, and.... Heck! Not a sign of anything. And we were two chaps who were to tackle a do-or-die mission and receive secret orders from our new O.C. You know, Freddy, I'm beginning to think, it's all a lot of hog wash. But why Air Marshal Manners should hand out all that fancy stuff sure beats me."

"I'm just as much in the dark myself," Freddy grunted. "But somehow I don't think that it was supposed to be this way. I think that something went wrong some place, and Manners had to hold up our special orders. Or perhaps he wanted us to get well acquainted with things. I mean, make it definitely look as though we were just a couple of replacements."

"Maybe so," Dave sighed and stared at the flock of British destroyers steaming out to take over and lead the convoy into port. "Maybe so, but I still don't like it. So help me, I doubt I'd be able to recognize a Nazi plane now if one should fall into my lap. Well, there're the destroyers, so this trick is over. Send the code signal to Plymouth Base that we've made contact and are coming in. And tell Sergeant Black aft that I'll have another slub of that coffee before we go in. And tell him I mean coffee, not tea!"

"A regular barbarian, drinking that horrible stuff!" Freddy groaned and adjusted his radio mike. "I swear, we'll never be able to make you a real Englishman!"

"It's still coffee!" Dave said with a grin. "And hurry it along, my little man."

A few minutes later the Catalina flyingboat had left the convoy far behind and safely in the charge of the destroyers. A cup of warm coffee was in Dave's stomach, and he was almost becoming slightly satisfied with the world again. Now, if only about forty-'leven Nazi planes would show up and give them a little action everything would be all to the merry. No hope of that, though, he reflected gloomily. They were too near to Base, and any Jerry lad who showed his nose around Plymouth Base just naturally didn't get back to Germany. The Jerries knew that and so they stayed well clear of that little bit of England.

"And what about the great mystery, Dave?" Freddy suddenly spoke up to break his train of thought. "Do you think we should go to Squadron Leader Hays and tell him our story?"

"Meaning your boy friend, Flying Officer Steffins?" Dave echoed with a frown.

"None other," the English youth replied. "I told you there was something queer about that chap. I really think we should speak to Squadron Leader Hays about him."

Dave made no comment for a few moments. During these two days at Plymouth Base he had thought a lot of thoughts about the queer acting R.A.F. pilot they had met on the train coming down. And the most important thought was the fact that neither he nor Freddy had so much as set eyes on the man since the moment he had picked himself up off the compartment floor after the Nazi plane strafe and gone forward to his own seat. The man had simply vanished into thin air. He most certainly had not reported at Plymouth Base. Freddy had made sure of that by asking all around. As a matter of fact, nobody at Plymouth Base had even heard of the man. And the bulletin board in the mess had said in so much black type that Dawson and Farmer were the only two replacements posted to Seventy-Four.

"Sorry to wake you up, Dave," Freddy spoke again. "But what do you think about the situation?"

"Pipe down, I was thinking," Dave growled. "But I can't even get to first base. Maybe we should speak to the Squadron Leader, yet that might make us look like a couple of saps. If there's one thing that gets a fellow's goat in this war it's the dizzy unfounded spy scares that pop up every time you turn a corner. And after all, to us he was just a yellow belly who shot off his face and asked a lot of questions. Maybe he was just some bird posing as an R.A.F. officer just for the heck of it. That sort of thing's happened before. You know, some bird wants to make an impression on his girl and he goes calling all dolled up as an officer, when he really should be wearing his private's uniform. No, Freddy, I don't think Squadron Leader Hays would love us extra much if we went to him with such a crazy story."

"I'm afraid you're right," Freddy grunted. "It is just a little bit crazy. But I still swear he's the same chap I bumped into in front of Adastral House."

"Well, maybe that time he was calling on a girl who likes the Army best," Dave chuckled. "Anyway, let's skip it for the time being. There's Base, and here we go down to a stack of warm food, and a little shut eye."

Dave's statement was half truth and half falsehood. They did put away a stack of food, but there was to be no shut-eye for either of them. They had hardly finished their meal when an orderly appeared with word that they were to report at once to Squadron Leader Hays' office. They exchanged looks, grinned happily, and instantly lost all desire for sleep.

"Hot dog!" Dave breathed and pushed back from the table. "Maybe this is it!"

"I'm saying nothing until I'm dead sure," Freddy grunted and got up, too. "The way things are going perhaps we're to be favored with the special honor of washing dishes."

"Boy, can you make a guy feel good!" Dave growled and gave his best pal a playful poke in the ribs.

When they reached the Squadron Leader's their hopes dropped a little for the simple reason that they were not the only two summoned. There were ten other pilots there as well. Squadron Leader Hays waited until Dave and Freddy had settled themselves in chairs and then started to speak.

"Special job for you fellows," he said. "Coastal Command is testing out a new type of plane to be used on short range work. It's the new Fairey "Fulmar" fighter. It's powered with a Bristol Pegasus engine that's been jacked up a bit to give a couple of hundred more horsepower than the ordinary Pegasus. It's a land job, of course, but it's been fitted with extra tanks, and sections of the wings are sealed so that you'll float for quite a bit of time in case you fall down into the drink. Whether these Fulmars will give us the service Coastal Command demands remains to be seen. Anyway, six of them arrived last night, and I've selected you chaps to give them a good testing. If you can find any off-shore Nazi planes then so much the better. However, don't go too far out, and don't get too close to the French coast. You can be sure that the Jerries are just aching to shoot down a Fulmar and get a good look at it. Well, that's all. They're out on the line now, and the mechanics are waiting. You can take off any time you want."

The Squadron Leader made a little gesture with his hand that dismissed the group. Disappointment tugging at their hearts, Dave and Freddy started toward the Squadron Office door, but pulled up short as the Commanding Officer spoke again.

"Oh, Dawson and Farmer!" he called out. "Wait a moment, will you?"

Both youths wheeled around with hope soaring up anew. The Squadron Leader waited until all the others had left, then grimaced and sighed unhappily.

"Darnedest war I ever fought in!" he growled and motioned to the boys to step closer. "There's enough blasted hush-hush stuff to smother the whole Empire. Of course what I told the others was plain rot. We've got Fulmars here, and they are to stay for keeps. This testing idea is all bosh. But orders are orders. So there's nothing I can do about it."

The Squadron Leader made another face and took a sealed envelop from out of his inside tunic pocket. He handed it to Dave.

"Your orders for something or other," he said. "Don't read them until you're in the air. And don't bother asking me questions. I don't know a blessed thing about them. What's more, I don't want to know. This arrived from Air Marshal Manners an hour ago. Here, take it, and get on with your job. Stuff it in your tunic pocket and keep it there until you're in the air. And.... Well, naturally, good luck and all that sort of thing. Now, buzz off, both of you."

Dave and Freddy saluted, executed a snappy about face and walked on air out of the squadron office and over toward the south side of the field where Six Fairey Fulmar fighter planes were lined up with engines ticking over. From the depths of dread and despair they had soared up to a new high. The long awaited event had come to pass at last. The sealed orders in Dave's pocket seemed to turn into a white hot coal that burned right through his clothing to his skin. He couldn't speak because excitement and eager expectation was like a hand of steel clutching at his throat. Sealed orders. For what? For life, or for death? Right now neither of them cared very much. One thing was certain. Those sealed orders meant action, and action was all that mattered to those two fisted, stout hearted, steel clawed birdmen of the Royal Air Force.