“I don’t mind much. Show me the park.” “Righto.” They walked out together. “Watson, old man,” said Antony, as soon as they were away from the house, “you really mustn’t talk so loudly indoors. There was a gentleman outside, just behind you, all the time.” “Oh, I say,” said Bill, going pink. “I’m awfully sorry. So that’s why you were talking such rot.” “Partly, yes. And partly because I do feel rather bright this morning. We’re going to have a busy day.” “Are we really? What are we going to do?” “They’re going to drag the pond—beg its pardon, the lake. Where is the lake?” “We’re on the way to it now, if you’d like to see it.” “We may as well look at it. Do you haunt the lake much in the ordinary way?” “Oh, no, rather not. There’s nothing to do there.” “You can’t bathe?” “Well, I shouldn’t care to. Too dirty.” “I see.... This is the way we came yesterday, isn’t it? The way to the village?” “Yes. We go off a bit to the right directly. What are they dragging it for?” “Mark.” “Oh, rot,” said Bill uneasily. He was silent for a little, and then, forgetting his uncomfortable thoughts in his sudden remembrance of the exciting times they were having, said eagerly, “I say, when are we going to look for that passage?” “We can’t do very much while Cayley’s in the house.” “What about this afternoon when they’re dragging the pond? He’s sure to be there.” Antony shook his head. “There’s something I _must_ do this afternoon,” he said. “Of course we might have time for both.” “Has Cayley got to be out of the house for the other thing too?” “Well, I think he ought to be.” “I say, is it anything rather exciting?” “I don’t know. It might be rather interesting. I daresay I could do it at some other time, but I rather fancy it at three o’clock, somehow. I’ve been specially keeping it back for then.” “I say, what fun! You _do_ want me, don’t you?” “Of course I do. Only, Bill don’t talk about things _in_side the house, unless I begin. There’s a good Watson.” “I won’t. I swear I won’t.” They had come to the pond—Mark’s lake—and they walked silently round it. When they had made the circle, Antony sat down on the grass, and relit his pipe. Bill followed his example. “Well, Mark isn’t there,” said Antony. “No,” said Bill. “At least, I don’t quite see why you know he isn’t.” “It isn’t ‘knowing,’ it’s ‘guessing,’” said Antony rapidly. “It’s much easier to shoot yourself than to drown yourself, and if Mark had wanted to shoot himself in the water, with some idea of not letting the body be found, he’d have put big stones in his pockets, and the only big stones are near the water’s edge, and they would have left marks, and they haven’t, and therefore he didn’t, and—oh, bother the pond; that can wait till this afternoon. Bill, where does the secret passage begin?” “Well, that’s what we’ve got to find out, isn’t it?” “Yes. You see, my idea is this.”