A photographer wants to be a detective and has an adventure trying to find a woman's uncle, but he is nearly executed for murder.
Ronnie Jackson (Bob Hope) finishes his last meal on death row in San Quentin. The warden lets him tell his story to reporters.
In San Francisco he takes photos of babies. Ronnie tells Sam McCloud (Alan Ladd) that he wants to be a detective, but Sam says no and leaves town. Carlotta Montay (Dorothy Lamour) comes in and asks for help finding her husband, and she gives Ronnie a precious ring and a map. He goes to a gated mansion, where Kismet (Peter Lorre) takes his coat and gun. Carlotta is singing and says they are looking for her uncle. Major Simon Montague (Charles Dingle) comes in and takes Ronnie to Baron Montay (Frank Puglia) and Dr. Lundau (John Hoyt), who says Carlotta is mentally ill. Ronnie gives the ring back to Carlotta, but she embraces him. Ronnie is leaving but looks for his gun. He takes a photo and drives off. Kismet chases him in a car and shoots at him. Ronnie escapes and develops the photo. Ronnie takes a drink and passes out, enabling Kismet to burn the film.
Ronnie takes police to question Kismet, but no one else is there. At night Ronnie climbs in a window. He goes to a sanitarium, thinking it is a lodge and plays golf with an inmate who uses an invisible ball. Willie (Lon Chaney Jr.) takes Ronnie to Kismet. Carlotta greets her uncle, the Baron Montay. Montague demands the map, and Kismet clubs Ronnie. James Collins tells Ronnie that they are looking for uranium, and Collins is shot dead. Ronnie avoids police and flies with Carlotta to Washington.
Ronnie and Carlotta see Baron Montay in a hotel full of police detectives. Ronnie is wanted for the murder of Collins. Ronnie gets a job as a bellboy and sees Montague. Carlotta works as a maid. Willie notices Ronnie, but the gang won't listen to him. Carlotta and Ronnie find a recording machine. Carlotta gets Montague and Kismet to talk while Ronnie tries to record them. Montague wants the codes from her uncle, and Kismet says he killed Collins. Ronnie emerges from under the desk with a gun, and Carlotta goes for help. Kismet kicks the gun out the window, but Lt. Hennessey comes in. Kismet switches the records, and Ronnie is arrested for murder. Montay gets the map.
The reporters leave Ronnie's cell, and he goes with the warden. Carlotta tells Ronnie that he is free because of a photo he took. Baron Montay thanks Ronnie for saving his life.
This comedy satirizes detective stories. Uranium has
become the key ingredient wanted by the bad guys.