As Berry and I Were Saying by Dornford Yates

hadn’t arrived, but there was a stranger there…sitting at Harker’s table…staring at me…
    “Well, I stared back. I mean, the man wasn’t waiting – he was at work on some brief…and sitting at Harker’s table…in Harker’s room…
    “Well, we stared at each other in silence.
    “Then something made me throw a glance round. The room was different. The red leather chair was gone, and instead of the one engraving, two cartoons by Spy were above the mantelpiece.
    “A frightful thought came to my mind.
    “‘My God,’ I said. And then, ‘Tell me, is this the third floor?’
    “He nodded.
    “‘That’s right. The third floor,’ he said.
    “I never remember feeling such a fool. I had walked past our front door on the second floor, and climbed to the third, there to invade the privacy of the chambers exactly above. Except for the furniture, they were exactly like ours. And much of the furniture was the same.
    “Consumed with mortification, I did the best I could. I apologized abjectly, explained that I belonged to the chambers below and that for some strange reason, for which I could not account, I must have walked up three flights, instead of two.
    “From being pardonably sticky, the fellow became quite civil and said it didn’t matter at all. Perhaps it didn’t to him: but it did to me. I bowed myself out of his room, slunk through the hall, picked up my hat and coat and stole downstairs, like a thief.
    “Harker hadn’t arrived, so I sat down in front of his fire and wondered what he would say, when he heard what I’d done. I was still too hot and bothered to look at The Times .
    “About seven minutes later Harker arrived.
    “I think I shall always see him, standing in the doorway of his room, with his hat on the back of his head and his overcoat over his arm, staring at me, with his hand clapped fast to his mouth.
    “‘Whatever’s the matter?’ I said, and got to my feet.
    “‘Boy,’ he said, ‘I’ve done the most awful thing. The most damned awful thing that I’ve ever done.’
    “‘Tell me,’ said I. But I didn’t have to be told. I knew. His words and his demeanour were too familiar.
    “‘Well,’ he said, ‘I entered the hall, as usual, and the first thing I noticed was that the clerks–’
    “‘–had moved the hat-stand,’ said I. ‘You needn’t go on. Ten minutes ago I did the very same thing. Walked into the chambers upstairs and into your room.’
    “‘Oh, I can’t believe it,’ said Harker. ‘And a fellow sitting at my table?’
    “‘That’s right,’ said I. ‘He didn’t seem too pleased, but he thawed a bit when I crawled – as I had to do.’
    “‘That’s more than he did with me. His manner was just black ice. And how could I protest? I never felt such a fool in all my life.’
    “‘You can hardly blame him,’ said I. ‘Once, yes. That is just possible. But twice in the same ten minutes…’ I shook my head. ‘Of course he’s now convinced that we were having him on.’
    “Well, there we are. That is exactly what happened. And to this day, I cannot imagine why. I went out and scanned the staircase, to see if there was something which might have misled us both. But there was nothing at all.”
    “That,” said my sister, “is most remarkable.”
    “Yes,” said Berry, “it is. And I think that it should go in. It’s evidence of something supernatural. On that particular morning some influence was at work in Number One Brick Court. An evil spirit or something was playing his knavish tricks.”
    “And the man was a stranger?” said Jill.
    “Yes,” said I. “That he had the chambers above means nothing at all. You can live above or below a man in The Temple for five years or more – and never know him by sight. Gill’s chambers were below ours. Though we used the same stairs, I never saw him there once.”
    “Did you ever know a coincidence in a case?”
    “I did – on one occasion. No damage was done. But there were two