Surgeon-Major Thomson had apparently forgotten his appointment to view camp bedsteads, for, a few minutes after he had left Geraldine and her brother, his taxicab set him down before a sombre-looking house in Adelphi Terrace. He passed through the open doorway, up two flights of stairs, drew a key of somewhat peculiar shape from his pocket and opened a door in front of him. He found himself in a very small hall, from which there was no egress save through yet another door, through which he passed and stepped into a large but singularly bare-looking apartment. Three great safes were ranged along one side of the wall, piles of newspapers and maps were strewn all over a long table, and a huge Ordnance map of the French and Belgian Frontiers stood upon an easel. The only occupant of the apartment was a man who was sitting before a typewriter in front of the window. He turned his head and rose at Thomson's entrance, a rather short, keen-looking young man, his face slightly pitted with smallpox, his mouth hard and firm, his eyes deep-set and bright.
"Anything happened, Ambrose?"
"A dispatch, sir," was the brief reply.
"From the War Office?"
"No, sir, it came direct."
Thomson drew the thin sheet of paper from its envelope and swept a space for himself at the corner of the table. Then he unlocked one of the safes and drew out from an inner drawer a parchment book bound in brown vellum. He spread out the dispatch and read it carefully. It had been handed in at a town near the Belgian frontier about eight hours before:--Fifty thousand camp bedsteads are urgently required for neighbourhood of La Guir. Please do your best for us, the matter is urgent. Double mattress if possible. London.
For a matter of ten minutes Thomson was busy with his pencil and the code-book. When he had finished, he studied thoughtfully the message which he had transcribed:--Plans for attack on La Guir communicated. Attack foiled. Believe Smith in London.
"Anything important, sir?" the young man at the typewriter asked.
Thomson nodded but made no immediate reply. He first of all carefully destroyed the message which he had received, and the transcription, and watched the fragments of paper burn into ashes. Then he replaced the code-book in the safe, which he carefully locked, and strolled towards the window. He stood for several minutes looking out towards the Thames.
"The same thing has happened again at La Guir," he said at last.
"Any clue?"
"None. They say that he is in London now."
The two men looked at one another for a moment in grave silence. Ambrose leaned back in his chair and frowned heavily.
"Through our lines, through Boulogne, across the Channel, through Dover Station, out of Charing-Cross, through our own men and the best that Scotland Yard could do for us. In London, eh?"Thomson's face twitched convulsively. His teeth had come together with a little snap.
"You needn't play at being headquarters, Ambrose," he said hoarsely. "I know it seems like a miracle but there's a reason for that.""What is it?" Ambrose asked.
