When his mother eloped with an Italian opera singer, Louis Mazzini was cut off from her aristocratic family. After the family refuses to let her be buried in the family mausoleum, Louis avenges his mother's death by attempting to murder every family member who stands between himself and the family fortune. But when he finds himself torn between his longtime love and the widow of one of his victims, his plans go awry.

• Ealing Studios
• J. Arthur Rank Organisation
• Dennis Price
• Alec Guinness
• Joan Greenwood
• Valerie Hobson
• Audrey Fildes
• Miles Malleson
• Clive Morton
• John Penrose