"It is a little different with me, sir," said Frank. I'm an American."

"All the same," said Lord Hastings, "you're a British naval officer, no matter what your nativity."

"That's true, too, sir," Frank agreed. "I haven't thought of it in just that way."

"Well," said Lord Hastings, "I shall report then that Captain Templeton and First Lieutenant Chadwick will go aboard the Plymouth this evening."

"Very well, sir," said Jack.

This is the reason then that Jack and Frank found themselves aboard an American destroyer in the Irish sea.

Frank Chadwick, as we have seen, was an American. He had been in Italy with his father when the great war began. He had been shanghaied in Naples soon after Germany's declaration of war on France. When he came to his senses he found that his captors were a band of mutinous sailors. Aboard the vessel he found a second prisoner, who turned out to be a member of the British secret service.

Frank met Jack Templeton, a British youth, aboard the schooner. Jack came aboard in a peculiar way.

The schooner, in control of the mutineers, had put into a north African port for provisions. Now it chanced that the store where the mutineers sought to buy provisions was conducted by Jack. The lad was absent when the supplies were purchased and returned a few moments later to find that the mutineers had departed without making payment.

Jack's anger bubbled over. He put off for the schooner in a small boat.

Aboard, the chief of the mutineers refused the demand for payment. A fight ensued. Jack, facing heavy odds, sought refuge in the hold of the vessel, where he was made a prisoner.

During the night Jack was able to force his way from the hold into the cabin where Frank and the British secret service agent were held captives.

He released them, and joining forces, the three were able to overcome the mutineers and make themselves masters of the ship.

Now Jack Templeton was an experienced seaman and knew more than the rudiments of navigation. Under his direction the schooner returned to the little African port that he called home. There the three erstwhile prisoners left the ship to the mutineers.

Later, through the good offices of the British secret service, Frank and Jack made the acquaintance of Lord Hastings, also in the diplomatic service. They were able to render some service to the latter and later accompanied him to his home in London. There, at their request, Lord Hastings, who in the meantime had been given command of a ship of war, had them attached to his ship with the rank of midshipmen.

Both Jack and Frank had risen swiftly in the British service. They had seen active service in all quarters of the globe and had fought under many flags.

Under Lord Hastings' command they had been with the British fleet in the North Sea when it struck the first decisive blow against the Germans just off Helgoland. Later they were found under the Tricolor of France and with the Italians in the Adriatic. With the British fleet again when it sallied forth to clear the seven seas of enemy vessels, they had traversed the Atlantic, the Pacific and the Indian oceans. It had been their fortune, too, to see considerable land fighting. They had been with the Anglo-Japanese forces in the east and had conducted raiding parties in some of the German colonial possessions.

Several times they had successfully run the blockade in the Kiel canal, passing through the narrow straits in submarines just out of reach of the foe. In Russia, they had, early in the war, lent invaluable assistance to the Czar; and more lately, they had been in the eastern monarchy when Czar Nicholas had been forced to renounce his throne.

Once since the war began they had been to America. This was shortly after the United States entered the war. They were ordered to the North Atlantic in order to help the American authorities snare a German commerce raider which, in some unaccountable manner, had run the British blockade in the North sea, and was wreaking havoc with allied shipping. Later they went to New York, and then returned to Europe with a combined British-American convoy for the first expeditionary force to cross the seas.

In temperament and disposition Jack and Frank were as unlike as one could conceive. Jack, big for his age, broad-shouldered and strong, was always cool and collected. Frank, on the other hand, was of a more fiery nature, easily angered and often rash and reckless. Jack's steadying influence had often kept the two out of trouble, or brought them through safely when they were in difficulties.

Both lads spoke French and German fluently and each had a smattering of Italian. Also, as the result of several trips to Russia, they had a few words of the Russian tongue at their command.

In physical strength, Jack excelled Frank by far, although the latter was by no means a weakling. On the other hand again, Frank was a crack shot with either rifle or revolver; in fact, he was such an excellent marksman as to cause his chum no little degree of envy. Then, too, both lads were proficient in the art of self defense and both had learned to hold their own with the sword.

Up to the time this story opens the combined allied fleets had succeeded in keeping the Germans bottled up in the strong fortress of Helgoland.

True, the enemy several times had sallied forth in few numbers, apparently seeking to run the blockade in an effort to prey upon allied merchant ships. But every time they had offered battle they had received the worst of it. They had been staggered with a terrible defeat at Jutland almost a year before this story opens, and since that time had not ventured forth.

But even now, in the security of their hiding places, the Germans were meditating a bold stroke. Submarines were being coaled and victualed in preparation for a dash across the Atlantic. Already, one enemy submarine--a merchantman--had passed the allied ships blocking the English channel and had crossed to America and returned. Some months later, a U-Boat of the war type had followed suit. A cordon of ally ships had been thrown around American ports to snare this venturesome submarine on its return, but it had eluded them and returned safely to its home port.

But soon--very soon, indeed--German undersea craft were to strike a more severe blow at allied shipping, carrying, for the moment, the war in all its horrors to the very door of America. While the United States was arming and equipping its millions to send across the sea to destroy the kaiser and German militarism, these enemy undersea craft were crossing the Atlantic determined to reap a rich harvest upon American, allied and neutral shipping off the American coast.

And the blow was to be delivered without warning--almost.

When the U.S.S. Plymouth, under Jack's command, returned to Liverpool, the captain of the vessel, having somewhat recovered, came aboard and relieved Jack of command.

"I'm obliged for your services, Captain," he said, "but I'll take charge of the old scow again myself, with your leave."

Jack and Frank went ashore, where, at their hotel, they received a brief telegram from Lord Hastings. It read as follows:

"Return to Dover at once. Important."

"Now I wonder what is up," said Frank after reading the message.

"The simplest way to find out," replied Jack, "is to go and see."

CHAPTER III

OFF FOR AMERICA

"Then everything went first rate your first trip, Captain?" questioned Lord Hastings.

"First rate, sir," Jack replied.

The lads were back in Dover where, the first thing after their arrival, they sought an audience with their former commander.

"Yes, sir," Frank agreed, "Jack makes an A-1 captain."

"I'm glad to hear it," was Lord Hastings' comment. "I've other work in hand and I wouldn't want to trust it to a man who is nervous under fire."

"But we were not under fire this time, sir," said Jack.

"You mustn't always take me literally, Jack," smiled Lord Hastings. "It was your first venture in your present rank and you acquitted yourself creditably. That is what I meant."

"And what is the other venture, sir?" Frank asked eagerly.

"There you go again, Frank," said Lord Hastings. "How many times have I told you that you must restrain your impatience."

Frank was abashed.

"Your warnings don't seem to do much good, I'll admit, sir. Nevertheless, I'll try to do better."

"See that you do," returned Lord Hastings gravely. "Nothing was ever gained by too great impatience. Remember that."

"I'll try, sir."

"Very well. Then I shall acquaint you with the nature of the work in hand."

The boys listened intently to Lord Hastings' next words.