“No. No, of course it doesn’t.” Bill gave a sigh of relief. “He’s just shielding Mark, what?” “I wonder.” “Well, isn’t that the simplest explanation?” “It’s the simplest if you’re a friend of Cayley and want to let him down lightly. But then I’m not, you see.” “Why isn’t it simple, anyhow?” “Well, let’s have the explanation then, and I’ll undertake to give you a simpler one afterwards. Go on. Only remember—the key is on the outside of the door to start with.” “Yes; well, I don’t mind that. Mark goes in to see his brother, and they quarrel and all the rest of it, just as Cayley was saying. Cayley hears the shot, and in order to give Mark time to get away, locks the door, puts the key in his pocket and pretends that Mark has locked the door, and that he can’t get in. How’s that?” “Hopeless, Watson, hopeless.” “Why?” “How does Cayley know that it is Mark who has shot Robert, and not the other way round?” “Oh!” said Bill, rather upset. “Yes.” He thought for a moment, “All right. Say that Cayley has gone into the room first, and seen Robert on the ground.” “Well?” “Well, there you are.” “And what does he say to Mark? That it’s a fine afternoon; and could he lend him a pocket-handkerchief? Or does he ask him what’s happened?” “Well, of course, I suppose he asks what happened,” said Bill reluctantly. “And what does Mark say?” “Explains that the revolver went off accidentally during a struggle.” “Whereupon Cayley shields him by—by doing what, Bill? Encouraging him to do the damn silliest thing that any man could possibly do—confess his guilt by running away!” “No, that’s rather hopeless, isn’t it?” Bill thought again. “Well,” he said reluctantly, “suppose Mark confessed that he’d murdered his brother?” “That’s better, Bill. Don’t be afraid of getting away from the accident idea. Well then, your new theory is this. Mark confesses to Cayley that he shot Robert on purpose, and Cayley decides, even at the risk of committing perjury, and getting into trouble himself, to help Mark to escape. Is that right?” Bill nodded. “Well then, I want to ask you two questions. First, is it possible, as I said before dinner, that any man would commit such an idiotic murder—a murder that puts the rope so very tightly round his neck? Secondly, if Cayley is prepared to perjure himself for Mark (as he has to, anyway, now), wouldn’t it be simpler for him to say that he was in the office all the time, and that Robert’s death was accidental?” Bill considered this carefully, and then nodded slowly again. “Yes, my simple explanation is a wash-out,” he said. “Now let’s have yours.” Antony did not answer him. He had begun to think about something quite different. CHAPTER IX. Possibilities of a Croquet Set “What’s the matter?” said Bill sharply. Antony looked round at him with raised eyebrows. “You’ve thought of something suddenly,” said Bill. “What is it?” Antony laughed. “My dear Watson,” he said, “you aren’t supposed to be as clever as this.”