"Then we'll come back and put the airships out of commission as carefully as possible." "That's easy enough. All we have to do is to let out the 'gas.'" "Next we'll have to go through the commander's pockets without arousing him." "That's more difficult, but I suppose it can be done." "Next we'll have to get our hydroplane to the water. Fortunately, we came down closer to the sea than the others. We should be able to do that without awakening the sleepers." "Then," said Frank, "we climb in and say goodbye, eh?" "That's it." "All right. We'll work it that way then. It's as good as any other. Now we'll keep quiet until we are sure everyone is asleep." Their plans thus arranged, the lads became quiet. They said not a word as they waited for sleep to overcome the Germans, but gazed out quietly over the dark sea. CHAPTER IX THE PLAN WORKS--ALMOST "Time to get busy." It was Frank who spoke. All was quiet among the sand dunes. The commander of the Germans had laid down upon the ground, some distance from the others, half an hour before. Snores from various points announced that most of the men were sleeping soundly. Jack and Frank got to their feet "Careful," said Jack as they separated. "Remember, don't give your man a chance to let out a cry." Frank nodded in the darkness and walked slowly toward the sentinel he had selected to silence. Jack moved in the other direction. As Jack came within a few yards of his prey, the man raised his rifle and commanded: "Halt!" "It's all right," said Jack. "I couldn't sleep and it was lonesome back there. I want company." The German lowered his rifle. "It's lonesome here, too," he said. "Wish you had been selected for my job." "I wouldn't have minded it tonight," said Jack, approaching closer. The German reached in his pocket and produced a pack of cigarettes. He extended the pack to Jack. "Have one?" he invited. Jack accepted a cigarette. The German produced a match. He laid his rifle upon the ground as he struck the match upon the leg of his trousers. It was the moment for which Jack had been waiting. Quickly his revolver leaped out. In almost the same instant he reversed it and before the German realized what was about to happen he brought the butt down on the man's head with great force. The man fell to the ground without a sound. Frank, advancing upon the other German, also was challenged when he drew close, but he, too, engaged his prey in conversation. As the man turned his head for a moment to gaze across the dark sand, the lad struck him violently over the head with his revolver butt. The German dropped like a log. A few moments later Frank and Jack met again near the first aeroplane. "It'll have to be quick work here," Jack warned "We haven't a whole lot of time, you know."