Director Michael Curtiz masterfully tells the fictional story of radio host Alexander Grandison (Claude Rains) as derived from a novel by Charlotte Armstrong. Grandison spookily recites murder mysteries on his radio show, with intimate and excruciating details. The reason he's so good and popular is that some of the murders he presents really are his own. He kills one of his female workers, but her fiancée, Steven Francis Howard (Michael North), threatens to take revenge for her death. Howard tries to convince Grandison's niece, Matilda Frazier (Joan Caulfield), that he is her long-lost husband. Much mystery and intrigue follows.