At two o'clock in the morning on the fifth of April, 1817, I stood in an elegant bedchamber in Berkeley Square and looked down at the dead body of Mr. Henry Turner.

Mr. Turner was in his twenties. He had brown hair arranged in fashionable, drooping curls and wore a black suit with an ivory and silver waistcoat, elegant pantaloons, and dancing slippers. An emerald stickpin glittered in his cravat, and his collar points were exceedingly high.

Only a slight red gash marred the waistcoat where a knife had gone in to stop his life. Except for the waxen paleness of his face, Mr. Turner might be asleep.

"And he died where?" I asked.

"In a little anteroom off the ballroom downstairs," Milton Pomeroy, my former sergeant, now a Bow Street Runner said. "Right in the middle of a fancy ball with the creme de la creme. Lord Gillis had him brought up here, so the guests would not be disturbed by a dead body, so he said."

Lord Gillis was an earl who lived in this opulent mansion on Berkeley Square. Tonight he had hosted a ball which the top of society had attended, including Lucius Grenville, Lady Breckenridge, Lady Jersey, and the Duke of Wellington.

Colonel Brandon and Louisa Brandon had been invited also because Lord Gillis had been an officer before he'd inherited his title, and he loved to gossip with military men-at least those ranked colonel and above.

After supper had finished and dancing had recommenced-about midnight-Mr. Turner had been found in a small anteroom, alone and dead.

"What about the weapon?" I asked.

For answer, Pomeroy held up a knife. It was slim and utilitarian, with a plain handle, unmarked. I'd had one much like it in the army and regretted its loss when I wagered it away in a game of cards.