Having returned to Paris from an extended holiday in Corsica, Lord Peter Wimsey receives news that his sister Mary's fiancé, Captain Denis Cathcart, has been found shot dead outside the Wimseys' shooting lodge at Riddlesdale in Yorkshire. His brother, Gerald, Duke of Denver, has been arrested for the murder. Cathcart was killed by a bullet from Denver's revolver, and Denver's only alibi is that he was out for a walk at the time Cathcart died. Lord Peter investigates!

Dorothy Leigh Sayers (13 June 1893 – 17 December 1957) was a renowned English crime writer, poet, playwright, essayist, translator and Christian humanist. She was also a student of classical and modern languages. She is best known for her mysteries, a series of novels and short stories set between the First and Second World Wars that feature English aristocrat and amateur sleuth Lord Peter Wimsey, that remain popular to this day. However, Sayers herself considered her translation of Dante's Divine Comedy to be her best work. She is also known for her plays, literary criticism and essays.