"There was a little passage in front of me, unpapered and uncarpeted, which turned at a right angle at the farther end. Round this corner were three doors in a line, the first and third of which were open. They each led into an empty room, dusty and cheerless, with two windows in the one and one in the other, so thick with dirt that the evening light glimmered dimly through them. The centre door was closed, and across the outside of it had been fastened one of the broad bars of an iron bed, padlocked at one end to a ring in the wall, and fastened at the other with stout cord. The door itself was locked as well, and the key was not there. This barricaded door corresponded clearly with the shuttered window outside, and yet I could see by the glimmer from beneath it that the room was not in darkness. Evidently there was a skylight which let in light from above. As I stood in the passage gazing at the sinister door and wondering what secret it might veil, I suddenly heard the sound of steps within the room and saw a shadow pass backward and forward against the little slit of dim light which shone............