It was as I feared when I left you.  The secret service must
  have rummaged my baggage both here and at the hotel.  They
  have taken some very valuable papers of mine.

“Secret service—­rummage baggage?” repeated Burke, himself now in perplexity.  “That is news to me.  We have rummaged no trunks or bags, least of all Nordheim’s.  In fact, we have never been able to find them at all.”

“Upstairs, Burke—­the servants’ quarters,” interrupted Craig impatiently.  “We are wasting time here.”

Mrs. Brainard offered no protest.  I began to think that the whole thing was indeed a surprise to her, and that she had, in fact, been reading, instead of making a studied effort to appear surprised at our intrusion.

Room after room was flung open without finding any one, until we reached the attic, which had been finished off into several rooms.  One door was closed.  Craig opened it cautiously.  It was pitch dark in spite of the broad daylight outside.  We entered gingerly.

On the floor lay two dark piles of something.  My foot touched one of them.  I drew back in horror at the feeling.  It was the body of a man.

Kennedy struck a light, and as he bent over in its little circle of radiance, he disclosed a ghastly scene.

“Hari-kiri!” he ejaculated.  “They must have got my message to Burke and have seen that the house was surrounded.”

The two Japanese servants had committed suicide.

“Wh-what does it all mean?” gasped Mrs. Brainard, who had followed us upstairs with Gladys.

Burke’s lip curled slightly and he was about to speak.

“It means,” hastened Kennedy, “that you have been double crossed, Mrs. Brainard.  Nordheim stole those plans of Captain Shirley’s submarine for his Titan Iron Works.  Then the Japs stole them from his baggage at the hotel.  He thought the secret service had them.  The Japs waited here just long enough to try the plans against the Z99 herself—­to destroy Captain Shirley’s work by his own method of destruction.  It was clever, clever.  It would make his labours seem like a failure and would discourage others from keeping up the experiments.  They had planned to steal a march on the world.  Every time the Z99 was out they worked up here with their improvised wireless until they found the wave-length Shirley was using.  It took fifteen or twenty minutes, but they managed, finally, to interfere so that they sent the submarine to the bottom of the harbour.  Instead of being the criminal, Burke, Mrs. Brainard is the victim, the victim both of Nordheim and of her servants.”

Craig had thrown open a window and had dropped down on his knees before a little stove by which the room was heated.  He was poking eagerly in a pile of charred paper and linen.

“Shirley,” he cried, “your secret is safe, even though the duplicate plans were stolen.  There will be no more interference.”

The Captain seized Craig by both hands and wrung them like the handle of a pump.