In Rio de Janeiro, nightclub singer Lola Dean accepts the proposal of Clarke Denton, then insists on hosting a celebratory dinner for their acquaintances, Ken and Joan Reynolds, Grace Ellis and Bill Kellogg. Clarke agrees and Lola then performs her act, which is watched by Honolulu detective Charlie Chan, his son Jimmy and Rio de Janeiro police chief Souto, who are there to arrest Lola for the murder of Manuel Cardozo in Honolulu a year and a half previously. Chan decides to arrest Lola quietly at her home. After she leaves the club with Clarke, she follows the advice of her secretary, Helen Ashby, and visits Alfredo Marana, a noted psychic. Marana drugs his patients with an herbal ingredient placed on a cigarette that is stimulated by coffee, and after Lola is drugged, Marana records her confessing to killing Manuel because she was in love with him and he would not leave his wife for her. On the way home, Lola persuades Clarke to elope that evening with her to the United States, and she begins to pack immediately. While Helen is telling Lola's guests about the impending elopement, Chan, Jimmy and Souto arrive, and soon after, Lola is found in her bedroom, stabbed to death, with a broken brooch lying next to her. Helen tells Chan about Lola's visit to Marana and about the persistent attentions of a mysterious man named Paul Wagner. Souto has the two men brought to the house, where Wagner admits that Lola was his ex-wife and that he came to see her earlier in an attempt to win her back. Upon hearing of her engagement to Clarke, however, Wagner left the house. Marana then plays the record of Lola's session and demonstrates his trance-inducing methods on Jimmy. Chan discovers that the pin of the brooch in Lola's room is broken off and deduces that it is imbedded in the killer's shoe. While Chan and Souto investigate, Jimmy finds jewelry taken from Lola's room in the room of Rice the butler. Rice admits to stealing the items but denies killing Lola, and before he can name the murderer, the lights go out and he is shot. Chan then finds the brooch pin in Helen's shoe and suggests that Marana put her in a trance to make her confess. She smokes one of the cigarettes but maintains that she is innocent. After smoking the rest of Helen's cigarette, Chan determines that Marana gave her one that was not drugged in order to protect her. Although Marana, whose real name is Alfredo Cardozo, protests that he killed Lola and Rice to avenge his brother, Helen confesses that she committed the murders because she is actually Barbara Cardozo, Manuel's widow. Helen had wanted to take Lola and the recording to the police the next day, but her elopement with Clarke would have enabled Lola to escape. Rice saw her with Lola's body, and Helen killed him to keep him quiet. Souto arrests Helen, after which Chan informs Jimmy that he has been drafted into the army, and Jimmy replies that the war will be a cinch with him in it.