I was early at the monument in the morning, and getting behind the stone signalled to the Castle roof in case Marjory should happen to expect me and be there. But there was no answer. So I sat down to wait till it would be decent time to go to the Castle for an early breakfast. As I sat waiting I thought I heard a sound, either close to me and muffled, or else distant; I could hardly tell which. Matters might be lively if I were discovered; so I got my revolver ready. With my heart beating so heavily that I mistook it at moments for the foreign sound, I listened and listened, all ears. It was as I had suspected; the sound came from the tunnel beneath me. I hardly knew whether to stay or go. If I waited I could see who came from the opening; but on the other hand I should at once be known to have discovered the secret. Still as the stone might roll back at any moment, it was necessary that I should make up my mind; I should either go or stay. I decided that I would stay and make discovery at once. In any case should I succeed in capturing a blackmailer, or even in discovering or partially discovering his identity, I should be aiding in Marjory's safety. So I got my revolver ready; and standing back so that I could not be seen at once by any one emerging, waited. No one came; but I could still hear a slight sound. Filled with a growing unrest, I determined to take the initiative, and began to move close to the stone. As I looked, it began to quiver, and then to move slowly. As it rolled softly back I kept behind it so that I might not be seen; and waited with revolver ready and what patience I could. There was dead silence; and then a hand holding a revolver rested a moment on the edge of the opening. I knew the hand, and I knew the revolver, and I knew the quickness of both. I did not say a word or make a sound, till Marjory with an alert movement seemed to sweep up out of the opening and whirled round with ready pistol, as though suspecting an enemy on every side. Marjory, all covered with dust, her cheeks as white as snow, so that the smears of dust lay on them like soot; and eyes with pupils distended as in coming from the dark. For a few seconds she seemed hardly to recognise me; but when she did she sprang gladly into my arms. "Oh! Archie, I am glad to see you. It was so terrible and lonely in the dark. I began to fear I might never find my way out!" In the dark! I began to fear, and asked her: "But, dear one, how did you come; and why? Hadn't you got a light with you? Surely you didn't come unprepared, if you did venture into the cave!" Then in a rush she told me the whole story. How before dawn she had been waked by the dropping of the book and had hurried to the castle roof to watch the stone. With her field glass she had presently seen it move. She was then satisfied that the watchers had gone home; and had determined on a little adventure on her own account.