A bored young woman living in Santa Rosa, California, Charlotte "Charlie" Newton (Teresa Wright), is frustrated because nothing seems to be happening in her life. Then, she receives wonderful news: her uncle (for whom she was named), Charles Oakley (Joseph Cotten), is arriving for a visit. Two men show up pretending to conduct a survey. Graham speaks to Charlie privately, identifying himself as Detective Jack Graham (Macdonald Carey) and telling her that her uncle is one of two men suspected of being a serial killer known as the "Merry Widow Murderer", with a modus operandi of seducing, murdering and robbing wealthy widows. Charlie refuses to believe it at first, but she cannot help noticing her uncle acting suspiciously on several occasions. Particularly chilling is a family dinner conversation during which Uncle Charlie reveals his utter contempt for rich widows.