“My wife has gone upstairs.” There was a barely noticeable emphasis on the first two words.

“All right then, John. It’s funny, but this is the one part of the whole business I haven’t worked out in advance — how to tell you. You see, John — I… am… you.

“You mean,” John said with deliberate inanity, “I’m not myself?”

“No.” He’s recovering, Jack Breton thought with reluctant approval, but he’s got to take it seriously from the start. He dug deep into his memory.

“John! When you were thirteen, your cousin Louise stayed at your home for most of a summer. She was eighteen, well-proportioned. Also she had a bath, regular as clockwork, every Friday night. One afternoon about three weeks after she arrived you took a hand drill from the garage, put a three-thirty-seconds bit in it and drilled a hole in the bathroom ceiling. You drilled it at the widest part of the big Y-shaped crack that Dad never got around to fixing, so it wouldn’t be noticed.

“Dad had floored the central area of the roof space for storage, and he had sheeted in the sides, but you found you could move one of the corner panels aside and get over the bathroom. So you took an interest in photography that summer, John, and the roof space made an ideal dark room. Every Friday night — when Louise was in the bath — you went up there into the darkness and soft brown dust. You got over the bathroom and took off — “

“That’s enough!” John Breton took a step forward, pointing with one finger in baffled accusation. He was trembling slightly.

“Take it easy, John. I’m simply presenting my credentials. Nobody else in the whole world knows the facts I have just mentioned. The only reason I know them is the one I have already given you — I am you. I did those things, and I want you to listen to me.”

“I’ll have to listen to you now,” John said dully. “This has been one hell of an evening.”