The point upon which Joan’s plan hinged was that, owing to the shrubs in front of the building, it was possible to remain concealed in the shadows beside the porch, invisible from the road. She proposed, therefore, to stay at the door while Cheyne was carrying on operations within, and to ring if any one approached the house, adding a double knock if there was urgent danger. She would hold the newcomer with inquiries as to the whereabouts of the mythical Mrs. Bryce-Harris, thus insuring time for her companion to beat a retreat. She herself also would have time in which to vanish before her victims realized what had happened. Feeling, therefore, that he would have a margin in which to withdraw if flight became necessary, Cheyne set to work to force an entrance. He rapidly examined the doors and windows, but all were fastened as before. Choosing the window with the loose sash upon which he had already decided, he took his knife and tried to open the catch. The two sashes were “rabbitted” where they met, but he was able to push the blade up right through the overhanging wood of the upper sash and lever the catch round until it snapped clear. Then withdrawing the knife, he raised the bottom sash. A moment later he was standing on the scullery floor. His first care was to unlock and throw open the back door, so as to provide an emergency exit in case of need. Then he closed and refastened the scullery window, darkening with a pencil the wood where the knife had broken a splinter. As he said to himself, there was no kind of sense in calling attention to his visit. He crossed the hall and silently opened the front door to see that all was right with Joan. Then closing it again, he began a search of the house. The building was of old-fashioned design, a narrow hall running through its center from back to front. Five doors opened off this hall, leading to the dining room and the kitchen at one side, a sitting room and a kind of library or study at the other, and the garden at the back. Upstairs were four bedrooms—one unoccupied—and a servant’s room. Cheyne rapidly passed through the house searching for likely hiding places for the tracing. Soon he came to the conclusion that unless some freak place had been chosen, it would be in one of two places: either a big roll-top desk in the library or an old-fashioned escritoire in one of the bedrooms. Both of these were locked. Fortunately there was no safe. He decided to try the desk first. A gentle application of the jemmy burst its lock and he threw up the cover and sat down to go through the contents.