“So,” he said now, “it is a remarkable coincidence, is it not? Our three murder victims—Mrs. Harriet Sippel, Miss Ida Gransbury and Mr. Richard Negus—they arrive separately and appear to have nothing to do with one another. And yet all three share not merely the date of their deaths, which was yesterday, but also their date of arrival at the Bloxham Hotel: Wednesday.”

“What’s remarkable about it?” I asked. “Plenty of other guests must also have arrived on Wednesday in a hotel of this size. I mean, ones that have not been murdered.”

Poirot’s eyes looked as if they were about to burst forth from his head. I couldn’t see that I had said anything particularly shocking, so I pretended not to notice his consternation, and continued to tell him the facts of the case.

“Each of the victims was found inside his or her locked bedroom,” I said, feeling rather self-conscious about the “his or her” part. “The killer locked all three doors and made off with the keys—”

“Attendez,” Poirot interrupted. “You mean that the keys are missing. You cannot know that the murderer took them or has them now.”

I took a deep breath. “We suspect that the killer took the keys away with him. We’ve done a thorough search, and they are certainly not inside the rooms, nor anywhere else in the hotel.”

“My excellent staff have checked and confirmed that this is true,” said Lazzari.

Poirot said that he would like to perform his own thorough search of the three rooms. Lazzari joyously agreed, as if Poirot had proposed a tea party followed by dancing.

“Check all you like, but you won’t find the three room keys,” I said. “I’m telling you, the murderer took them. I don’t know what he did with them, but—”

“Perhaps he put them in his coat pocket, with one, or three, or five monogrammed cufflinks,” Poirot said coolly.

“Ah, now I see why they speak of you as the most splendid detective, Monsieur Poirot!” Lazzari exclaimed, though he can’t have understood Poirot’s remark. “You have a superb mind, they say!”

“Cause of death is looking very much like poisoning,” I said, disinclined to linger over descriptions of Poirot’s brilliance. “We think cyanide, which can work with great speed if the quantities are sufficient. The inquest’ll tell us for sure, but . . . almost certainly their drinks were poisoned. In the case of Harriet Sippel and Ida Gransbury, that drink was a cup of tea. In the case of Richard Negus, it was sherry.”

“How is this known?” Poirot asked. “The drinks are still there in the rooms?”

“The cups are, yes, and Negus’s sherry glass. Only the remaining few drops of the drinks themselves, but it’s easy enough to tell tea from coffee. We will find cyanide in those drops, I’ll wager.”

“And the time of death?”