“That’s more than I can say, Mr. Damon,” replied Tom, with a mournful shake of his head.  “I’m very sorry it happened, for it looks as though I hadn’t taken proper care.  The idea of those men stowing themselves away on board here, and me not knowing it; and then coming out unexpectedly and getting possession of the craft!  It doesn’t speak very well for my smartness.”

“Oh, well, Tom, anyone might have been fooled by those plotting foreigners,” said Mr. Damon.  “Now, we’ll try to turn matters about and get the best of them.  Oh, but it feels good to be free once more!”

He stretched his benumbed and stiffened limbs and then helped Tom free the others.  They stood up, looking at each other in their dimly lighted prison.

“Well, if this isn’t the limit I don’t know what is!” cried Ned Newton.

“They got the best of you, Tom,” spoke Lieutenant Marbury.

“Are they really foreign spies?” asked Captain Warner.

“Yes,” replied his assistant.  “They managed to carry out the plot we tried to frustrate.  It was a good trick, too, hiding on board, and coming out with a rush.”

“Is that what they did?” asked Mr. Damon.

“It looks so,” observed Tom.  “The attack must have started in the engine-room,” he went on, with a look at Mound and Ventor.  “What happened there?” he asked.

“Well, that’s about the way it was,” answered the engineer.  “We were working away, making some adjustments, oiling the parts and seeing that everything was running smoothly, when, all at once, I heard Koku yell.  He had gone in the oil room.  At first I thought something had gone wrong with the ship, but, when I looked at the giant, I saw he was being attacked by four strange men.  And, before I, or any of the other men, could do anything, they all swarmed down on us.

“There must have been a dozen of them, and they simply overwhelmed us.  One of them hit Koku on the head with an iron bar, and that took all the fight out of the giant, or the story might have been a different one.  As it was, we were overpowered, and that’s all I know until we were carried in here, and saw you folks all tied up as we were.”

“They burst in on us in the same way,” Tom explained.  “But where did they come from?  Where were they hiding?”

“In the oil and gasoline storeroom that opens out of the motor compartment,” answered Mound, the engineer.  “It isn’t half full, you know, and there’s room for more than a dozen men in it.  They must have gone in some time last night, when the airship was in the hangar, and remained hidden among the boxes and barrels until they got ready to come out and overpower us.”

“That’s it,” decided Tom.  “But I don’t understand how they got in.  The hangar was well guarded all night.”

“Some of your men might have been bribed,” suggested Ned.

“Yes, that is so,” admitted Tom, and, later, he learned that such had been the case.  The foreign spies, for such they were, had managed to corrupt one of Tom’s trusted employees, who had looked the other way when La Foy and his fellow-conspirators sneaked into the airship shed and secreted themselves.