Dr. Mary Wells is a psychoanalyst, whose patient, Cecily Johnson, is playing the part of Stella in a new production of "A Streetcar Named Desire." Cecily gives the doctor two tickets to see a performance of the play. She invites Lt. John Franklin, a detective who is her lover, to accompany her. During a particularly rowdy scene, the sound of a shot is heard. The audience thinks it is part of the play, until the stage manager comes out and announces that a person has been shot back stage and the performance cannot continue. The murdered man is the actor playing Stanley Kowalski. Lt. Franklin takes on the case. After checking out the ballistics and interrogating the cast, he and Dr. Wells conclude that one of the actors in the play was the killer. They consider possible motives for the murder by each actor. Utilizing Dr. Wells' psychological expertise and Lt. Franklin's experience and perceptiveness, they are able to eliminate some performers, while others remain under suspicion. Through an idea of Dr. Wells to have the cast reenact the death scene, she and the Lieutenant are able to discover and apprehend the killer.