"The white walls of the Hotel St. Antoine rose in a rectangle around the sunny court, casting long shadows across the basin of the fountain. The strip of blue overhead was cloudless. Sparrows twittered under the eaves the yellow awnings fluttered, the flowers swayed in the summer breeze, and the jet of the fountain splashed among the water-plants. On the sunny side of the piazza the tables were vacant; on the shady side I was lazily aware that the tables behind me were occupied, but I was indifferent as to their occupants, partly because I shunned all tourists, partly because I was thinking of my great-aunt. "Most old ladies are eccentric, but there is a limit, and my great-aunt had overstepped it. I had believed her to be wealthy--she died bankrupt. Still, I knew there was one thing she did possess, and that was the famous Crimson Diamond. Now, of course, you know who my great-aunt was. "Excepting the Koh-i-noor and the Regent, this enormous and unique stone was, as everybody knows, the most valuable gem in existence. Any ordinary person would have placed that diamond in a safe-deposit. My great-aunt did nothing of the kind. She kept it in a small velvet bag, which she carried about her neck. She never took it off, but wore it dangling openly on her heavy silk gown. "In this same bag she also carried dried catnip-leaves, of which she was inordinately fond. Nobody but myself, her only living relative, knew that the Crimson Diamond lay among the sprigs of catnip in the little velvet bag. "'Harold,' she would say, 'do you think I'm a fool? If I place the Crimson Diamond in any safe-deposit vault in New York, somebody will steal it, sooner or later.' Then she would nibble a sprig of catnip and peer cunningly at me. I loathed the odor of catnip and she knew it. I also loathed cats. This also she knew, and of course surrounded herself with a dozen. Poor old lady! One day she was found dead in her bed in her apartments at the Waldorf. The doctor said she died from natural causes. The only other occupant of her sleeping-room was a cat. The cat fled when we broke open the door, and I heard that she was received and cherished by some eccentric people in a neighboring apartment. "Now, although my great-aunt's death was due to purely natural causes, there was one very startling and disagreeable feature of the case. The velvet bag containing the Crimson Diamond had disappeared. Every inch of the apartment was searched, the floors torn up, the walls dismantled, but the Crimson Diamond had vanished. Chief of Police Conlon detailed four of his best men on the case, and, as I had nothing better to do, I enrolled myself as a volunteer. I also offered $25,000 reward for the recovery of the gem. All New York was agog.