Adapted from Arthur Richman's play with improvisation and directed by AA-winning Leo McCarey, a couple, suspicious of each other, divorce but sabotage each other's new romances until they re-unite.
Jerry Warriner (Cary Grant) tans under a lamp to show he was in Florida but finds his wife Lucy Warriner (Irene Dunne) coming in late with her voice teacher Armand (Alexander D'Arcy). Jerry says he is not suspicious but urges Armand to leave. Lucy doubts that Jerry was in Florida and says that doubt ruins marriage, suggesting divorce. She calls her lawyer, who says marriage is beautiful as he snaps at his wife. In court Jerry and Lucy argue over custody of their dog, but Lucy wins him with a trick.
Aunt Patsy (Cecil Cunningham) is bored living with Lucy and brings in neighbor Dan Leeson (Ralph Bellamy), an Oklahoma oil-man. Jerry comes in to visit the dog and plays the piano while the dog barks. Patsy warns Lucy about the rebound, but Lucy says she likes Dan. At a nightclub Jerry is with Dixie Belle Lee (Joyce Compton), and they join Lucy and Dan. Jerry makes fun of Lucy marrying Dan, pretending he is glad. Dixie sings "Gone With the Wind" as a floor fan blows her dress up. Dan dances with Lucy.
Dan off-key and Lucy sing "Home on the Range." Jerry comes in and reminisces about Lucy. Dan's mother (Esther Dale) comes in with gossip about Lucy's divorce. Jerry denies it and says he was to blame. Jerry hopes the three will be happy. Lucy finds Jerry in her apartment; but he hides and tickles her as Dan reads her a love poem. Armand calls Lucy about his date. Lucy kisses Dan, making him jubilant. Jerry goes to Armand's apartment and finds Lucy singing to people; he falls off his chair. Lucy tells Patsy she can't marry Dan, because she is still in love with Jerry. Armand calls and hides before Jerry comes in. Jerry apologizes to Lucy; but the dog finds Armand's hat, which Jerry realizes is too big for him. When Dan and his mother call, Jerry goes in the bedroom with Armand. The others hear them fighting as Mrs. Leeson apologizes. Armand and Jerry run through, and Dan leaves disappointed.
Lucy sees a news photo of Jerry with Barbara Vance (Molly Lamont), and Jerry has fun with Barbara, resulting in engagement. Lucy calls on Jerry the day their divorce is final. They drink champagne and recall his promise to love her always. Barbara calls, and Jerry says that Lucy's voice is his sister. Jerry calls on Barbara and her parents. Lucy comes in as his sister Lola - acting crudely, asking for a drink, calling Jerry the nipper, and pretending to get drunk. She sings a sexy version of "Gone With the Wind," leaving with Jerry. Two cops stop them, and she lets her car roll into a ditch. They ride on motorcycles to her father's. The door between the rooms opens. Amid double-talk Jerry admits he was a fool and joins her minutes before the divorce takes effect.
This witty comedy shows two clever people very much in love, playing various games, revealing that no one else can come between them for long.