"They are all here," he said. "You can let him go now." Jack stepped back and the German shook himself angrily. "You'll pay for this," he shouted angrily. "Why, we expect to," said Lord Hastings smoothly, "we expect to pay for it with our big guns, which, with the help you have extended to us by giving us these plans, will make the task easier." The German doubled his fists and took a step forward. Jack smiled at him. "I wouldn't even think of it if I were you," he said quietly. The German drew back. "And shall we let him go now?" asked Lord Hastings. "He is simply a burden to us, you know." The German's face lighted up. "We can hardly do that, much as we would like to," said Jack. "You see, he might tell them all ashore that we have their plans, and they would naturally change them. As it is, believing that he has been drowned, the Kaiser will simply appoint a new military governor and use the plan of campaign already decided upon." "True," said Lord Hastings. "Then we must keep this capture a secret." "Yes, sir," said Jack, "and now we may as well get away from here." "In the meantime," replied Lord Hastings, "his excellency shall be our guest. You may give the word to submerge, preparatory to departure, Mr. Templeton." Jack turned away. CHAPTER XXIX. THE LAST SHOT OF THE D-16. Running smoothly and swiftly the submarine passed from the Sea of Marmora back into the Dardanelles, and set out on the last lap of her journey. It was now after 7 o'clock in the morning, and a grey mist, heralding the approach of a storm, was in the air above. Gradually the swell of the waves increased as the wind grew in violence, and the waters of the strait grew angry. But below, where the D-16 moved swiftly along, all was smooth and tranquil, although the barometer showed a heavy disturbance above. The new military governor of Constantinople, desiring the freedom of the vessel rather than to be confined, had given his parole, and, seeming to take his plight with fortitude, was watching the workings of the vessel with the greatest interest. Some of the intricate details Lord Hastings took the trouble to explain to him. Then, just as the D-16 seemed about to accomplish the last lap of her return journey safely, the trouble occurred. Lord Hastings had given it as his opinion that they must at that moment be in the very heart of the Turkish fortifications in the strait, and had turned away, when the prisoner, with a sudden leap, sprang to the signal that controlled the air tanks. Before any one could stop him he had given the signal that sent the D-16 soaring to the top of the water, where she floated upon the surface not a hundred yards from the guns of the nearest Turkish fort. The wind had kicked the strait into an angry swirling mass of water, with the waves running high. But the D-16 had hardly been tossed upon the crest of the first wave when a Turkish sentry espied her.