The fifth entry in the Columbia series based on the CBS radio program, "The Whistler", opens with kindly old music store owner Edward Stillwell (Paul E. Burns) hiring private detective Don Gale (Richard Dix) to find a girl Stillwell hasn't seen in seven years. Gale sends Freida Hanson (Helen Mowery') to pose as the missing Elora Lund (Pamela Blake), and she learns that some items left by Elora's mother are now extremely valuable before Harry Pontos (Mike Mazurki) comes into the room and kills Stillwell. He also kidnaps Freida but releases her when Don announces she is an impostor. With Freida's help, Gale locates Pontos' apartment, who is shot down in a gun battle with the arriving police. Gale returns to his place but is arrested by detectives Taggart and Burns and jailed. The detectives later find the real Elora, who has been in a sanitarium recovering from an accident. Gale is released and Elora is sent by the detectives to see if he will disclose why Stillwell was looking for her. Gale, planning to cheat her, tells her what the secret treasure is. Gales disappears and becomes the object of a manhunt when he is wrongfully accused of killing Freida, who has been killed by James Summers, her apartment manager, who has also discovered the secret. Joan Hill, Gale's secretary, locates and warns him about the police. He tells her he is going to the record store to find some recordings made by Jenny Lind worth $200,000.