“The place gives me the creeps,” said Mary with a shudder, and her nervousness was not affectation. “The whole thing is frightful! Poor Thomas killed, and Harry taken away heaven knows where---- Oh!” She sprang to her feet, and her face had gone pale. “I know where Harry is,” she said, quivering with excitement. “I know, I know!” “Where?” asked the wondering Leslie. The girl ran out of the room into the hall. “Where is Mr. Alford?” she asked quickly. “I must see him at once.” “He telephoned from Red Farm,” said Leslie. “Perhaps we can get him.” She turned the handle of the old-fashioned instrument and gave the Red Farm number. “Is that you, Dick? How lucky!” “I expected it was you. Is anything wrong?” he asked anxiously. “No; Mary Wenner has something she wants to tell you.” She lowered her voice. “She thinks she knows where Harry is hidden.” There was a silence at the other end. “She’s not----” “No, no, no.” With Mary within earshot, it was impossible to assure Dick that the girl was not trying to make a sensation. “I’ll come over right away,” he said. They went out to the head of the drive to meet him, and Mary offered her theory. “I must have been mad not to have told you about this before. I don’t know where my wits have gone,” she said. “After all my treasure-hunting and the horrible experience I had that night with Gilder, and not to think of it now, when I practically came down to show Mr. Gwyn the place--well, I’m surprised at myself!” Dick listened with growing impatience to this preliminary. “Where do you think my brother is?” “Where?” said Miss Wenner triumphantly. “Why, under the Abbey--that’s where. I’ll show you.” They walked side by side across the meadow, and as they went Miss Wenner related the startling story of her adventures after treasure. “Of course, I always knew that it didn’t belong to me, even if I found it,” she said virtuously; “but Mr. Gilder was so very pressing that I couldn’t very well refuse him, especially after what he’d written in vanishing ink, though I’ve got the ink back again, as he’ll find out one of these days.” Leslie listened, scarcely crediting her ears. Yet, unless Mary Wenner had an imagination of a particularly inventive nature, it was hardly likely that she could have made the story up. Dick examined the great corner-stone of the tower. He stood by, watching curiously, whilst, with a pair of scissors which she took from her bag, the girl pressed back the catch and sent the corner-stone turning noisily on its invisible hinge. The opening was between twelve and fifteen inches wide. A stout man could never have entered by that way, as Dick pointed out. “You had better stay here; I’ll go down,” he said. “You’ll want a light,” warned Mary.