I wandered down into the dining-room, and dropped into a chair, and closed my eyes. Suddenly I remembered that it was that chair into which the girl had dropped when the doctor had said those words I did not understand. I sat up, very wide awake, remembering.
She was to walk along the eastern corridor, and was to come to a wall at the end. And yet she was to walk out into the air! What did it all mean? What trick was the man about to play upon her? What devilry was afoot?
I got up at once, and threw away my cigar, and set off to explore the house. I wanted to know where this eastern corridor was, if such a place existed, and what was meant by the doctor's words. I went up to my own room first, and made out, as well as I could, by remembering which way the sun rose, and other matters, in what direction the house was situated; and so came to the conclusion that the room to which I had been assigned was at the end of the eastern corridor, nearest to the great bulk of the house. Which is to say, that if I stood in the doorway of my room, and faced the corridor, the other rooms of the house would be on my right hand, while on my left the corridor stretched away into darkness, past rooms that, so far as I knew, were unoccupied.
Lest by any chance my windows should be watched, I lit the lamp in my room and left it; then I came out into the corridor, and closed the door. I looked over the head of the great staircase; the house was in complete silence, though not yet in darkness. Listening carefully, I moved away swiftly into the gathering darkness to the left, until at last, at the end of the corridor, my outstretched hand touched the wall. This was exactly as it should be, according to the doctor's words. I now turned my attention to the wall itself, and found that it was recessed—much as though at some time or other it had been a window that had been bricked up. I could make nothing of it, and I went back to my room, sorely puzzled.
I must have a torpid brain, for I was ever given to much sleeping. On this occasion I sank down into a chair, intending to sit there for a few minutes and think the matter out. In less than five, I was asleep. When I awoke I felt chilled and stiff, and I blamed myself heartily for not having gone to bed. While I yawned and stretched my arms, I became aware of a curious noise going on in the house. With my arms still raised above my head, I stopped to listen.
Whatever noise it was came from the end of the corridor where I had found that blank wall. Some instinct made me put out the light; then in the darkness I stole towards the door, and cautiously opened it. Outside the corridor was dark, or seemed to be at my first glance; I dropped to my knees, and peered round the edge of the door, looking to right and left.
To the right all was in darkness; the servants had gone to bed, after extinguishing the lights and locking up. To the left, strangely enough, a faint light shone; and as I turned my eyes in that direction I saw that a small hand-lamp was standing on the floor, and that above it loomed the figure of a man, casting a grotesque shadow on the walls and ceiling above him. I made enough of the figure to know that it was the doctor, and that he was working hard at that end wall.
I was puzzling my brains to know what he was doing, and was striving hard to connect his presence there with what he had said to the girl, when I heard a grinding and a creaking, and suddenly the lamp that stood beside him was blown out in a gust of wind that came down the corridor and touched my face softly as I knelt there. Then, to my utter amazement, I saw the night sky and the stars out beyond where that end wall had been.
I had just time to get back into my room and to close the door, when the doctor came tiptoeing back along the corridor, and vanished like a shadow into the shadows of the house. I waited for a time, and then struck a match, and looked at the little clock on the mantelpiece. It wanted four minutes of midnight.
I opened the door again, and looked out into the corridor; then, on an impulse, I stole along towards that newly-opened door, or whatever it was, and, coming to it, looked out into the night. It was at a greater height from the ground than I had thought possible, because on that side of the house the ground shelved away sharply, and there was in addition a deep, moat-like trough, into which the basement windows looked. More than ever puzzled, I was retracing my steps, when I heard a slight sound at the further end, like the light rustle of a garment mingled with the swift patter of feet.