and make yourself objectionable to Miss Norris. Borrow money from her, and that sort of thing.'
"He looked at me, with his bright little eyes, nodding eagerly.
"'Robert,' he said. 'Yes. How shall we work it?'
"There was really a Robert, Mr. Gillingham, as I have no doubt you and the Inspector both discovered. And he was a wastrel and he went to Australia. But he never came to the Red House on Tuesday afternoon. He couldn't have, because he died (unlamented) three years ago. But there was nobody who knew this, save Mark and myself, for Mark was the only one of the family left, his sister having died last year. Though I doubt, anyhow, if she knew whether Robert was alive or dead. He was not talked about.
"For the next two days Mark and I worked out our plans. You understand by now that our aims were not identical. Mark's endeavour was that his deception should last for, say, a couple of hours; mine that it should go to the grave with him. He had only to deceive Miss Norris and the other guests; I had to deceive the world. When he was dressed up as Robert, I was going to kill him. Robert would then be dead, Mark (of course) missing. What could anybody think but that Mark had killed Robert? But you see how important it was for Mark to enter fully into his latest (and last) impersonation. Half-measures would be fatal.
"You will say that it was impossible to do the thing thoroughly enough. I answer again that you
