A woman detective outpaces her police fiancé in solving a complicated murder case.
Oil heir Millard Lannon (John Eldredge) sues his wife Mona Lannon (Gloria Dickson) for custody of their son Robert. Lawyer Nat Flavin (Morgan Conway) argues that Mona is unfit because of her relationship with Donald Norton (John Ridgely). Detective Myrna Winslow (Jane Wyman) tells her boss Simmy Sanger (Selmer Jackson) she won't help the blackmail and calls police Lt. Jim Rickey (Dick Foran) to get married. Flavin has Millard call for police protection, saying Mona threatened him. Millard reprimands his chauffeur Chick (Jack Mower) for drinking and tells Flavin he is a convict. Mona calls on Millard and offers him money, but he wants $2,000 a month. Mona demands Robert. Millard tries to embrace her, and she runs out as Millard is shot dead.
Outside Myrna listens as Jim questions a neighbor and Flavin. Brody (Maxie Rosenbloom) finds a broken high heel. Myrna follows them to Mona's apartment and goes to meet Norton, waiting as he calls. Mona calls home, and Jim gets her number too. Myrna finds Mona and says that Norton is hiding. Mona confesses she killed Millard; but Myrna says she lied, because he was shot from outside. Myrna tells Mona to go to her apartment and gets Jim to follow her. Myrna gets away and tells Simmy they are working for Mona and that she found a shell outside the window. Flavin tells Norton he wants to defend Mona. Myrna climbs in the window and listens. Norton asks Flavin to defend him. Jim and Brody want Norton as a witness, but Norton pulls a gun and locks them in a room while Myrna uses a gun to leave with Norton. She asks Norton to confess and takes him to Mona, who wants her son Robert and suggests Chick may have him. Myrna calls Jim and says not to arrest Mona.
Myrna asks Flavin where Robert is, and he says he is now his guardian. Brody brings Myrna to the police because of the heel. Myrna tells Jim that Mona and Norton are in her apartment, but they find no one there and decide to wed. Jim listens as Myrna makes a call she is going to the zoo. Myrna then pretends to be a secretary to search Flavin's office and finds Millard's will. Myrna calls Jim as Flavin comes in. Flavin abducts Myrna. Jim reads what Myrna typed, suspects Flavin and goes to his house. There Flavin tells Chick he'll make Mona and Norton look like suicide. Norton gives Flavin money. Jim and Brody arrive and turn off the car in the garage, preventing Myrna from dying. They arrest Flavin; but Chick comes in with a gun, and they fight as Mona and Norton find Robert. Jim knocks Flavin out the window, and Brody knocks out Chick. Myrna finds Flavin and is embraced by Jim.
This compact mystery has humor and shows a capable woman