It was no easy matter to convince her, yet when Dorothy saw the condition of affairs, there was really nothing she could do but give in. For us to explore that unknown territory, without some line on the outside to protect us in case of peril, was manifestly unwise. Certainly it was not possible for us to let so plain a clue go by. At my command, the cabman drove past the old book store, up the street, and round the square. Back on the main thoroughfare again, I made ready to return and join Tom. “You’ve got the place fixed clearly in mind?” I asked, looking up at her from the sidewalk. To my surprise, Dorothy’s eyes were filled with tears, and her voice came pleadingly. “I wish you did not feel you had to go. I don’t know why I feel so strangely about your going, but I do. Isn’t there some other way out?” I felt my resolution waning, as an almost overmastering desire to seize her in my arms, in the face of shocked and respectable Bloomsbury, swept over me. “We’ve got to follow the trail to the end, Dorothy,” I answered. “Everything’s going to be all right, don’t worry.” As I turned away, I felt a light touch, almost like a caress, on my coat sleeve. Accident or not, no knight ever went into battle more inspired by his lady’s gage than I, bearing that accolade, strode towards the old book shop and the mysterious laboratory on the fifth floor. Tom greeted me eagerly as I reached the second story. “Not a sound from the laboratory,” he began. “And, luck of lucks, there’s an open, empty room opposite, where we can wait. Come on up.” Up the stairs and into the empty room we passed, pausing briefly to examine the blank and heavy door of the mysterious workers fastened by heavy locks. Our waiting place proved nothing more than a bare attic chamber, with a constricted view of roofs and chimney pots. “Not exactly the abode of luxury,” I said, glancing around critically, “but then it’s all in the day’s work. I’ve waited in worse places for a lot smaller stakes.” Folding his great coat for a cushion, Tom seated himself back against the wall. He had left the door a trace ajar. “I’m practically sure that there’s no one in there now, and we’ll wait here till they arrive. We shall be sure to hear them when they come up the stairs. By Jove, never thought of it. Not a thing to read with us. There’s the book shop downstairs; I wonder if I dare to try a sortie.” He thought a moment. “No, not yet, anyway. Tell you what I’ll do. Here’s a sporting proposition for you.” He pulled out his penknife and opened it. “Here’s a bully bare floor. I’ll play you a game of stick knife to while away the time.”