Frank and Jack, at this, slunk well back into the crowd, for they did not wish to be scrutinized closely. But they need have had no fear. The leader of the Germans laid a hand on the shoulders of the two men nearest him. "You two," he said, "shall stand guard the remainder of the night, one to the southeast and one to the southwest. But do not venture beyond the boundaries I have laid down." The Germans saluted and moved away. The leader moved toward the sea and none of the others followed him. Instead, some walked a short distance to the east, others to the south and still others to the west. They threw themselves down in the sand. A few remained near the airships. Frank and Jack walked a short distance toward the sea, but kept some distance behind the German leader, who stood looking off across the water, apparently deep in thought. The lads sat down upon the ground. "Well," said Frank, "what are we going to do about it?" "Do!" echoed Jack. "Why, there is only one thing we can do--one thing we must do! We must get away from here and warn the fleet!" "All right," said Frank, "it sounds easy; but how?" "Well, that doesn't make any difference. We've got to do it." "And the moment we have gone our absence will be discovered, the Germans will know the fleet has been warned and the attack will be given up," said Frank. "And we don't want anything like that to happen. It will be the first time the Germans have mustered up courage enough to come out and give battle. We don't want to frighten them off." "We don't want to let them sneak up on a part of our fleet unguarded, either," declared Jack. "Of course not. You say we must give the warning. We'll try, of course. But first, why not let's put all the aeroplanes except the one we want out of commission?" "By Jove! a good plan! We'll do it." "Exactly," said Frank. "Then there is still another thing." "What is that?" "Why, we want the instructions that fellow carries," and Frank waved a hand in the direction of the German leader. "He was kind enough to let us know he has them. We'll have to take them away from him." "Say!" exclaimed Jack, "you've laid out quite a job for us, haven't you?" "It's got to be done," declared Frank. "Well, all right, but we shall have to be careful." "Right you are," Frank agreed, "one little slip and the whole thing will be spoiled." "Then there must be no slip," said Jack, quietly "I agree with you there. Now the question arise? as how the thing may best be done." "We'll have to wait until they're all asleep," said Jack. "You forget the sentinels won't sleep," said Frank. "No, I don't; and they will be the first disposed of. They are not looking for enemies from within, you know. You walk up to one and I'll walk up to the other. We'll be challenged when we get close, of course. Then it will be up to us to silence those fellows before they can make an outcry." "We'll try it. Then what?"