After numerous newspaper headlines extol Lewis Nagel's exploits against crime, his superior, chief of police Alfred M. Kennedy, angered at being upstaged, promotes Nagel to captain so that he can transfer him to the quiet suburb of Fairview. Nagel's pal, reporter Steve Withers, follows him, certain that there will be a story. When asked by society matron "Muffin" Wilder to speak at her "Lady's Conversation and Get Together Club," Nagel meets her attractive niece, Jeane Sandford, who is visiting for the anniversary of her uncle Mark's death. Steve, seeing Jeane's interest in the excitement of crime, tries to flirt by talking about the dangers of Fairview, but she rebuffs him. That night, as a practical joke, Steve sneaks into Jeane's bedroom and takes her necklace, then is seen escaping by Edgar Keer, a jeweler. The next day, Jeane, after reporting the burglary, apologizes to Steve. Although Nagel orders Steve to return the necklace, it is stolen from him. The following evening, Mark Sandford's relatives gather at his abandoned house for the reading of his will by his attorney, Stuart Hackett, at midnight. In attendance are Jeane, Mrs. Wilder's nephew Ronald, who is a playwright and amateur criminologist, Ronald's wife Claire, the deceased's two brothers, Edmund and Herbert, and Herbert's wife Grace. In the will, Mark castigates all the relatives except for Jeane, to whom he has bequeathed his fortune, on condition that she has retained the necklace, which has instructions hidden in two of its stones. Keer peeps through the window and hears Jeane reveal that the necklace has been stolen. Hackett is about to open an envelope to read alternate instructions, when Nagel and Steve come out of hiding and Nagel persuades Hackett to give him forty-eight hours to find the necklace. The next day, Nagel asks Keer to make a phony necklace like the original, and that night, Nagel and Steve enter the house to plant the necklace as a ruse to catch the crook. After they find that someone has been sleeping in the house, they come across Hackett's dead body and part of the original necklace. Nagel arrests the relatives and interrogates them. Ronald takes everyone's fingerprints and finds that Steve's match those found on the sill of Jeane's window. Nagel arrests Steve, but after everyone but Jeane leaves, he asks her to give Steve the benefit of the doubt and wear the phony necklace, telling everyone that the fortune is hidden in the house, but that she is not to receive it until her upcoming birthday. Nagel lets Steve out of jail, and that night, after Nagel finds a vagrant in the house, Jeane, who has gone to try to find evidence to help Steve, finds Keer's body. She is then temporarily kidnapped, and the necklace is stolen. Nagel finds it in Edmund's pocket. Mrs. Wilder, gazing at Mark's portrait, notices that a wart is in fact a button. A panel in the wall opens when she pushes the button, revealing Herbert and Grace. Herbert confesses that when he got to the house, the panel was open. He says he shot Hackett in self-defense and took the necklace and surmises that Keer was in cahoots with Hackett. Steve calls his editor with the story, but Nagel demands that Kennedy's name, not his own, be used in the headline.