“I don’t know. I saw Poland Street written up. Why?”

“Well, because there’s something mysterious goes on in a house somewhere near here. Only a month ago we found the body of a young woman drowned in the main sewer at the corner of Charing Cross Road, and the affair is a mystery. The police ’ave kept it out of the papers while they make inquiries. We’re trying to find out what house has direct communication with the sewer, but up to the present we’ve not been successful. It’s a good job,” he added, “that you weren’t caught by the flush, for it must just be going down at this time.”

I explained how narrowly I had escaped death, and then in reply to the constable described the dastardly plot of which I had been the victim.

“Of course, sir, you won’t mind making a full statement at the police station, will you?” the officer said. “The discovery of the poor woman in the sewer the other day has shown that there is some house in which people mysteriously disappear. It is evidently to that house you were invited. You will be able to assist us to identify it.”

I shook my head, saying: “I fear that I’ll never be able to recognise it again, for I really took no notice of its exterior. It lies somewhere east of Regent Street, that is all I know.”

“Depend upon it that more than one person has been swept down by the flush,” declared the sewer-man. “A man’s body was found down at the outfall at Beckton about three months ago. He was in evening dress, and evidently a gentleman, our foreman said, but where he came from was a complete mystery. My own idea is that the house has no direct communication with the sewer, for if it had, we should have discovered it. You say, sir, that you fell through a hole in the stairs?”

I replied in the affirmative.

“Exactly. You dropped down into a cellar or somewhere in the basement, and then, while you were insensible, they put you into the sewer—through some manhole, perhaps, of which they have a duplicate key. The house must be near a manhole. That’s my belief.”

“Then you don’t think that I fell plumb into the sewer?”

“Certainly not. You were thrown into the sewer while insensible down a manhole, without a doubt. It’s lucky you just escaped the flush. The villain evidently knew that the flush is at eight o’clock in the morning, and that we don’t go down till afterwards. And when we go, well, the victim has, of course, disappeared. By Jove! sir,” added the big muscular man, standing astride in his big, high boots, “you’ve had a narrow shave, and no mistake.”