“I do not know where the key is,” replied von Bechtold, carelessly. “You may break the door down, if you wish, but you will not be repaid for your trouble.”

“I’ll take the trouble, anyway,” Darrin retorted. “Mr. Dalzell, your shoulder and mine both together.”

As the two young officers squared themselves for the assault on the door a black cloud appeared briefly on von Bechtold’s face. But as Darrin turned, after the first assault, the deep frown was succeeded by a dark smile of mockery.

Bump! bump! At the third assault the lock of the door gave way so that Dave and Dan saved themselves from pitching into the room headfirst.

“Oh, whew!” gasped Danny Grin.

An odor as of peach-stone kernels assailed their nostrils. They thought little of this. It was a sight, rather than the odor, that instantly claimed their attention.

For on the berth, over the coverlid, and fully dressed in civilian attire of good material, lay a man past fifty, stout and with prominent abdomen. He was bald-headed, the fringe of hair at the sides being strongly tinged with gray.

At first glance one might have believed the stranger to be merely asleep, though he would have been a sound sleeper who could slumber on while the door was crashing in. Dave stepped close to the berth.

Dalzell followed, and after them came the submarine’s commander.

“You will go back to the cabin and remain there, Mr. von Bechtold,” Dave directed, without too plain discourtesy. “Corporal, detail one of your men to remain with the prisoner, and see that he doesn’t come back here unless I send for him. Also see to it that he doesn’t do anything else except wait.”