As John Newberry and Maria Ivar, a husband and wife acting team, celebrate the closing night of their hit play, Maria becomes angry with John for describing, in his curtain speech, her role as "supporting." The argument continues in front of their producer/manager, Charles McNulty, and when both refuse to act with the other again, McNulty realizes that a real problem exists. Although they can be very sweet to each other, John and Maria are usually in a state of war. Anxious to preserve the team, McNulty reminds them that they are under contract to him as a team and tells them that they cannot appear anywhere separately. He convinces them to consult separate psychiatrists in order to resolve their problems, and both appear confident that their respective complaints about each other will be vindicated. While John consults with Dr. Harold Matson, Maria sees Dr. Susan Nash. After John tells Harold about his disputes with his wife, the doctor suggests hospitalization for him, not Maria. Susan, in turn, listens to Maria's complaints about John and recommends a nice, quiet sanitarium for her, not John. Determined to prove his points, John invites Harold to study his wife and invites him to stay with them, posing as an old college friend. Maria devises the same plan and intends to introduce Susan as a sorority sister from Vassar. Although Maria arranges for Susan to meet John over cocktails, Susan meets Harold first and assumes he is John, while Harold thinks she is Maria. The doctors begin to analyze each other until they are interrupted by McNulty, who expresses his opinion that John and Maria are both on the verge of nervous breakdowns. Through McNulty, Harold and Susan realize they are both doctors on similar missions, but John and Maria are unaware and continue to behave according to their original scenarios. Before he leaves, McNulty presents John and Maria with their show's closing financial statement. On looking it over, Maria finds that, one night, four hundred free tickets were given out to members of the "John Newberry Fan Club," further enraging her. John and Maria's fighting has infected their servants, Arthur and Ethel, who fight over which flavor of sherbet to serve that evening. The servants' battle spreads to the living room, and John ends up spending the night at his club. Later, John begins paying romantic attention to Susan, while Maria and Harold go out together. When John asks Harold if he is making any progress in his diagnosis of Maria, Harold informs him that Maria is "loosening up," an answer that John is not pleased to hear. Susan then reports much the same information about John to Maria. One day, when all four, plus Arthur, are on a picnic together, Harold tosses a horseshoe over his shoulder for luck and smashes the windshield on John's car. Harold advises everyone just to laugh off the incident but Maria throws a rock through Harold's windshield. Later, after Harold and Susan have separately suggested to them that each may be at fault at times, John and Maria announce to each other that all they want is to make the other happy. Although Harold and Susan hope to be able to leave soon and plan to continue seeing each other, they become embroiled in an argument about an incident involving John and Maria. To resolve Harold and Susan's dispute, John and Maria find themselves playing the roles of psychiatrists. The fight is interrupted when McNulty arrives with a copy of a new play he wants John and Maria to appear in and they agree to read it immediately. The play is about a shrewish wife who beats her husband, who is an awful liar. John and Maria, who are more or less reconciled, do not want to appear in something so violent and inappropriate to their new mood. When McNulty accuses the doctors of having ruined the finest acting team in the country, John and Maria deduce that they have both been under observation and another battle erupts between them. While arguing, they slip into performing a scene from the new play, and when they realize what is happening, they fall into each other's arms, happy at last.