Louis's mother married an Italian singer against the wishes of her titled family. They cast her and her son out of the family. Louis sets out for revenge and one by one offs those (all played by Alec Guinness) who stand between him and his dukedom. As part of his plan, he marries Edith, the widow of a cousin whom he killed. But he fails to take into account the greed of his childhood friend Sibella. She frames him for murder, then gets him released when he agrees to marry Edith. All seems well until he realizes he's left his memoirs, revealing his string of murders, in his prison cell.

A dark but hilarious comedy, somewhat slow-moving by today's standards, but brilliantly written.