In the upstairs offices of the Dunning Theatre, Broadway star Valerie Stanton argues bitterly with her longtime producer and former lover, Gordon Dunning. Valerie declares her intention to marry architect Michael Morrell and end both her personal and professional relationship with Gordon, but the domineering producer refuses to part with her. When Gordon threatens to tell Michael ugly lies about her past and then grabs her, Valerie becomes frightened and hits him over the head with a statuette. Realizing that she has killed him, Valerie slips downstairs without being noticed. While Valerie says goodbye to the cast and crew of her latest hit comedy, co-star Marian Webster finds Gordon's dead body. Later, in her apartment, Valerie recalls the events leading up to Gordon's demise: On the way to an opening night party at Gordon's, Valerie and Gordon argue about her desire to star in a production of Hedda Gabler . Although Valerie, who has made her name in comedies, is confident that she can play the dramatic part, Gordon belittles her ambition. At the party, Valerie meets Michael, a witty Englishman, and feels instantly attracted to him. Later that night, Valerie resumes her quarrel with Gordon about Hedda Gabler . Then, over Gordon's objections, Valerie lunches with Michael the next day and soon falls in love with him. Determined to sever all ties with Gordon, Valerie asks Marian, who loves the producer despite having been dumped by him ten years before, for help. Although Marian despises Valerie, she agrees to use whatever influence she has on Gordon to distract him from the star. In a theater restaurant, Marian tries to rekindle Gordon's feelings for her, but he is too preoccupied with Valerie to respond. When Valerie comes to his table and invites him to her home the next evening for a "business" talk, he assumes that she is returning to him. Gordon then tells Broadway reporter Jeff Trent that Valerie is going to star in his next show, and the item appears in the newspaper the next morning. When Valerie sees the announcement, she storms into Gordon's office and demands that he issue a retraction. Gordon refuses, and the fatal argument begins. Back in her apartment, Valerie is informed of Gordon's death and is summoned to the theater. There Captain Danbury, a theater-loving police detective, questions the cast and crew about their activities the previous night. During the interrogation, Marian, who is in a shock-induced coma at the hospital, is implicated in the crime, while Valerie is barely questioned. Later, Danbury shows Valerie a love letter that Gordon had written to her just before his death, as well as a letter of rejection addressed to Marian. When Valerie then learns that Danbury has Gordon's diary, she becomes concerned, but the detective only uncovers more damning information about Marian. While Danbury is visiting her one day, Valerie insists that Marian is innocent and, describing her actual movements at the murder scene, playfully suggests that she is the killer. Danbury, however, dismisses her "confession" because she has offered no motive for the crime. Marian then regains consciousness and, guessing Valerie's guilt, denounces her as a heartless killer. Marian's harsh condemnation moves Valerie to seek out Danbury, but as she is about to confess, the detective receives a call informing him that Marian has committed suicide. Completely undone by the news, Valerie is unable to concentrate during rehearsals for Hedda Gabler and appears headed for a breakdown. On opening night, Danbury informs her that he is closing the case, but Valerie cannot let go of her guilt, especially after the devoted Michael tells her that he has known the truth about the murder all along. Just before the curtain rises, Valerie scribbles a confessional note to Danbury and places it in the velvet gloves she wore while striking Gordon. Relieved of her burden, Valerie gives a stunning performance, then, after taking her curtain calls, gives herself up to Danbury.