From: Lord Peter Views the Body by Dorothy L. Sayers, 1928. Harper/Perennial, 1993.
The wife of a diamond merchant asks Lord Peter's help a scant nine hours before her husband's ship is scheduled to dock. An old acquaintance of hers, Paul Melville, with whom she had a regrettable affair, has stolen her diamond necklace and a portrait proving their affair. She would like Lord Peter to retrieve both before her husband can find out.
Lord Peter proceeds to engage Melville in a game of poker. In the sight of two others, he catches Melville cheating and threatens to ruin his reputation unless he hands over the necklace and portrait.
This is my first Lord Peter read. I don't know if I'd pick up one of the novels, but I'm intrigued enough by Wimsey to read more stories.