"Yes," said he, "that's the key;" and he added reproachfully, with no doubt a lively recollection of his mother's objurgations: "So you had it all the time." "I found it this morning, Dick," said I. "Where?" "In the shed on the Castle Down. Now, how the deuce did it get there? The dead sailormen had no use for keys." "It's very curious," said Dick. "Very curious and freakish," said I, and I sat down on the grass to think the matter out. "Let me see, your mother missed it in the morning after I came to Tresco." "That's three days ago." And I could hardly believe the boy. It seemed to me that months had passed. But he was right. "Yes, three days ago. Your mother missed it in the morning. It is likely, then, that it was taken from the lock of the door the night before." "That would be the night," said Dick, suspiciously, "when you tapped on my window." "The night, in fact, when I first landed on Tresco. Wait a little." Dick sat still upon the grass, and I took the key from his hand into mine. There were many questions which at that moment perplexed me--that hideous experience in Cullen Mayle's bedroom, the rifling of Adam Mayle's grave, the replacing of the plan in it and the disappearance of the cross, and I was in that state of mind when everything new and at all strange presented itself as a possible clue to the mystery. It seemed to me that the key which I held was very much more than a mere rusty iron key of a door that was never locked. I felt that it was the key to the door of the mystery which baffled me, and that feeling increased in me into a solid conviction as I held it in my hand. I seemed to see the door opening, and opening very slowly. The chamber beyond the door was dark, but my eyes would grow accustomed to the darkness if only I did not turn them aside. As it was, even now I began to see dim, shadowy things which, uncomprehended though they were, struck something of a thrill into my blood, and something of a chill, too. "The night that I landed upon Tresco," I said, "we crossed the Castle Down, I nearly fell on to the roof of the shed, where all the dead sailormen were screeching in unison." "Yes!" said Dick, in a low voice, and I too looked around me to see that we were not overheard. Dick moved a little nearer to me with an uneasy working of his shoulders. "Do you remember the woman who passed us?" I asked. "You said it was a woman." "And it was." I had the best of reasons to be positive upon that point. I had scratched my hand in the gorse and I had seen the blood of my scratches the next day on the dress of the woman who had brushed against me as she passed. That woman was Helen Mayle. Had she come from the shed? What did she need with the key? "Is that shed ever used?" I asked. "Not now." "Whom does it belong to?" He nodded over towards Merchant's Rock. "Then Adam Mayle used it?" "Cullen Mayle used it." "Cullen!"