The sinking of the German vessel related in the first chapter had been the first venture of the D-16, and now the vessel was heading toward the coast of England again, having gone as far toward the strong fortress of Heligoland as Lord Hastings had deemed advisable at that time. All day the little vessel continued on her way, traveling upon the surface, for there was now no need to submerge. She went very slowly, and night found her not many miles from the scene of her first encounter. A sharp lookout was kept for some sign of an enemy, but there was none. With the coming of the first light of day, Jack and Frank ascended the bridge together, and turned their eyes toward the west. A faint cloud of smoke on the horizon gave evidence of a ship of some sort. "Probably a British vessel," said Jack. "Can't tell," returned Frank. "A German cruiser may have succeeded in running the blockade and getting in behind." "That's true, too," Jack agreed. "It's a mystery to me how they do it. England is supposed to have them safely bottled up. It's beyond me how they get out." "It's beyond me, too. Of course, it's easy enough for the submarine; but you'd think we'd be bound to spot a big cruiser." "Something will have to be done, sooner or later. What's the use of a blockade if it doesn't blockade?" "Well," said Frank dryly, "I have no doubt that if you have a plan, the admiralty would be glad to know it." "I haven't any plan; but England will have to do something. That's certain." "There is no question about that. Hello!" "What's up?" asked Jack, looking at his friend in some surprise. For answer Frank pointed toward the east. Jack peered intently into the distance and also uttered an exclamation of surprise. "Germans?" he asked. "Must be," replied Frank briefly. He glanced ahead again. Then turned to his friend with an exclamation of satisfaction. "If they are," he said, "they'll get more than they bargained for this time." For what his eyes had made out, through his glass, was the outline of five large battle cruisers, convoyed by a flotilla of torpedo boats. "British?" asked Jack eagerly. "Look like it," replied Frank, "but I can't tell for sure." It was plain to both lads that neither fleet had made out the presence of the other, and both--the one from the West and the one from the East--were steaming directly toward the little submarine, which lay squarely between them, though out of sight, because she sat so low in the water. "Call Lord Hastings," said Jack, and Frank hastened to obey. A moment later the commander of the D-16 appeared on the bridge. He took in the situation at a glance. "The fleet to the east is German," he said, after a careful scrutiny through his glass, "and the other must be the British fleet commanded by Admiral Beatty." "Then there will be a fight," said Frank.