“It may be. I should advise that the building be closely watched, even to the extent of hiding watchers in the cellar, but you must be very careful. Personally I hope you do not catch any one to-night, nor for several nights, until I have completed my work. Of course I don’t mean that you are to let a building burn down,” added Grace smilingly. “Are you quite certain of Miss Marshall?” “Yes! No doubt at all about her.” Grace told him of what she had heard and seen on the other side of the Rhine when she was on her way across to the American lines. “Thank you!” he exclaimed after a brief reflection over what she told him, but offered no further comment on the subject of the woman who appeared to Grace to be playing a double game. “How long do you believe it will take you to gather in the ends of the clues you have? I take it that is what you mean?” “That is it exactly, sir. Perhaps a day or two; perhaps longer. If I make as much headway in the next twenty-four hours as I have done in the last, I may be able to close my case in less time. Please be careful how you communicate with me and never do so at my billet. What do you know about Doctor Klein, my landlord? I wish to be certain about what sort of a house I am living in. You see Miss Briggs and I being alone makes some difference.” The captain chuckled and stroked his chin, Grace regarding him solemnly. The Intelligence officer understood in a way why she asked the question. “He is one of the finest Germans I know, Mrs. Gray, and that is much for me to say about a Hun. I might say considerably more, but I am going to let you work out your own problem. You will be surprised when you get yourself set straight on this matter.” “Thank you. I am sure I do not know what you mean. I will report as soon as I have something further of a definite nature for you,” promised Grace, rising to go to her work. “Do you need assistance?” “No, thank you. There are too many persons mixed up in this affair already.” “Clever woman! If you wish anything, let me know.” “Well, sir, so long as you have made the offer, I do need some assistance. If convenient I should like the loan of an auger.” “A what?” “Auger, sir, to bore holes with.” “Are you in earnest?” “I am, sir. I wish one about two inches in diameter if I can get it, but if not I can use a smaller one. I should like to have a saw, but I fear I cannot use it to advantage.” “Are you thinking of building a house?” questioned the officer whimsically. “No, sir, but I am going to partially tear down one. When may I have it?” “Now. I will order it, or shall I send it to the canteen?” “Neither, I think,” decided Grace after refection. “I think I shall have some one call for it. Please see that it is well wrapped so that no one can tell from the appearance of the package what is in it. Good morning, sir. I must return to the canteen or I shall be in difficulties,” she added laughingly, and saluting, walked out without another word.