Nina and Robert Tracey (Judy Holliday and Jack Lemmon), married for eight years, suffer marital problems and divorce. Robert shares the home of his womanizing Navy buddy Charlie Nelson (Jack Carson) while Nina looks to her interfering mother for guidance. Robert spends an evening with Janis (Kim Novak), who finds the dashing Robert "real cute" but he feels uncomfortable with Janis and other girls he dates. Nina also tries to date other men. Although they try to ignore each other when they accidentally meet, it is obvious that the past is not dead. Then one night, they find themselves in a nightclub, dancing the mambo together; they had both learned to dance since their divorce. Later, after a disastrous meeting at her home with Charlie, Nina tells her mother on the phone that she is still in love with Robert. He accidentally overhears the conversation, having dashed to her home because of his friend's reputation. Nina and Robert reconcile and remarry.