Masterpiece Theatre Lord Peter Wimsey, the best-bred detective in the United Kingdom, is back ferreting out crime among the privileged classes. Lord Wimsey returns from a tour of Europe to learn that Capt. Dennis Cathcart, who was engaged to marry P... (more)eter's sister Lady Mary Wimsey, was murdered while fleeing the grounds of Riddlesdale, the Wimsey family's estate, in the middle of the night. Peter's brother, the Duke of Denver, is considered the prime suspect in the crime by the police, but Lord Wimsey is convinced there's more to the case than what's on the surface, and the deeper he digs, the more certain he becomes that his brother is not the murderer ... and his sister has some secrets she's not sharing. In Part 1: Lord Peter Wimsey's brother, the Duke of Denver, is suspected of murder.