"What fact?" he asked. "That I, with my friend Ashton, am in possession of certain discoveries by which we can, under given conditions, bring Zeppelins to the ground." The red-tabbed captain curled his lip in a rather supercilious smile. He was evidently one of those persons imported into the Department after the outbreak of war and, in comparison with Barton as an investigator, was a nonentity. True, a piece of paper bearing a message in the enemy's cipher had been found secreted in Roseye's card-case. But I argued that before the owner of the card-case could be condemned, she must be found, and an explanation demanded of her. "You surely cannot condemn an accused person in her absence!" I argued. Barton agreed with me. It was against all principles of justice to condemn an accused person unheard. "Well," explained the red-tabbed captain, "upon the face of it, there can be no real defence. Here we have the missing lady's belongings found in a tunnel, and in them--fortunately, for ourselves--we discover a message intended for transmission to the enemy. That message, Mr Munro, is quite plain, and speaks for itself. You have made an interesting scientific discovery. Possibly they have ferreted out your secret. It interests them: they fear you and, therefore, they have plotted your death." "I won't believe that!" I cried in angry resentment. "Ask yourself! Would you yourself believe it of the woman whom you loved?" "My dear Mr Munro," replied the captain coldly, "we are at war now. We cannot gauge either our feelings, or our beliefs, by the standard of pre-war days." "Well," I declared bluntly, "I don't believe it. Miss Lethmere would never hold any communication with the enemy. Of that I'm quite positive." "But we have it written down here--in black and white!" "True. But before we take this as authentic we must discover her, and question her. To you mysterious people of the Secret Service the task will, surely, not be so very difficult. You know the mystery of Miss Lethmere's sudden and unaccountable disappearance. Therefore I leave all to you--to investigate, and to elucidate the puzzle. I don't pretend to account for it. You, both of you, of the War Intelligence Department and the Special Branch of Scotland Yard, have the facts before you--plain facts--the disappearance of Lady Lethmere's daughter. When her whereabouts is ascertained then the remainder of the inquiry is surely quite easy. I am not an investigator," I added with biting sarcasm. "I'm only an inventor, and I leave it to you both to discover why Miss Lethmere disappeared." "You apparently have invented something of which the enemy is determined, at all hazards, to learn the truth," remarked Inspector Barton. I laughed, and slowly took a cigarette from my case.