Wimsey and Bunter try to save Lord Peter's elder brother, the Duke of Denver, from the hangman's silk noose when he is accused of murdering Dennis Cathcart, who was engaged to his sister, Lady Mary. Cathcart was shot in the Duke's garden during the night, and the only suspect was found standing by the body - but he declines to discuss the matter. Denver stands by his right to be tried by his peers amid the Gothic splendour of the House of Lords.