“I may as well tell you,” she said, at length.  “It is no secret in our set, and I suppose you would find it out soon, anyhow.  It is said that he is engaged to Mrs. Brainard—­that is all.”

“Engaged?” repeated Burke.  “Then that would account for his being at the hotel here.  At least, it would offer an excuse.”

Gladys was not slow to note the stress that Burke laid on the last word.

“Oh, impossible,” she began hurriedly, “impossible that he could have known anything about this other matter.  Why, she told me he was to sail suddenly for Germany and came up here for a last visit before he went, and to arrange to come back on his return.  Oh, he could know nothing—­impossible.”

“Why impossible?” persisted Burke.  “They have submarines in Germany, don’t they?  And rival companies, too.”

“Who have rival companies?” inquired a familiar voice.  It was Captain Shirley, who had returned out of breath from his long climb up the steps from the shore.

“The Germans.  I was speaking of an attache named Nordheim.”

“Who is Nordheim?” inquired the captain.

“You met him at the Naval building, that night, don’t you remember?” replied Gladys.

“Oh, yes, I believe I do—­dimly.  He was the man who seemed so devoted to Mrs. Brainard.”

“I think he is, too, father,” she replied hastily.  “He has been suddenly called to Berlin and planned to spend the last few days here, at the hotel, so as to be near her.  She told me that he had been ordered back to Washington again before he sailed and had had to cut his visit short.”

“When did you first notice the interference with the Turtle?” asked Burke.  “I received your message this morning.”

“Yesterday morning was the first,” replied the captain.

“He arrived the night before and did not leave until yesterday afternoon,” remarked Burke.

“And we arrived to-night,” put in Craig quietly.  “The interference is going on yet.”

“Then the Japs,” I cut in, at last giving voice to the suspicion I had of the clever little Orientals.

“They could not have stolen the plans,” asserted Burke, shaking his head.  “No, Nordheim and Mrs. Brainard were the only ones who could have got into the draughting room the night of the Manila celebration.”

“Burke,” said Kennedy, rising, “I wish you would take me into town.  There are a few messages I would like to send.  You will excuse us, Captain, for a few hours?  Good evening, Miss Shirley.”  As he bowed I heard Kennedy add to her:  “Don’t worry about your father.  Everything will come out all right soon.”

Outside, in the car which Burke had hired, Craig added:  “Not to town.  That was an excuse not to alarm Miss Shirley too much over her friend.  Take us over past the Stamford cottage, first.”

The Stamford cottage was on the beach, between the shore front and the road.  It was not a new place but was built in the hideous style of some thirty years ago with all sorts of little turned and knobby ornaments.  We paused down the road a bit, though not long enough to attract attention.  There were lights on every floor of the cottage, although most of the neighbouring cottages were dark.