An acting student goes undercover to prove a singing star killed her husband.

In London, as budding actress Eve Gill helps a frantic Jonathan Cooper escape from the police, he relates the events that led to his being accused of murder: Actress Charlotte Inwood, Jonathan's lover, arrives at his door, her dress covered in blood, and tells him that she killed her husband during a quarrel. Believing it would be best for Charlotte to perform as usual, Jonathan goes to her house to get her a clean dress. After he collects the dress, he arranges things to look as if a thief broke in and killed Charlotte's husband. As he is leaving, however, Charlotte's maid, Nellie Goode, appears unexpectedly and sees him. He hurries home, where Charlotte suggests that he hide out. Telephoning Eve's house, he learns from her mother that Eve is rehearsing at the Royal Academy of Dramatic Arts. The police arrive to question him and pursue the runaway Jonathan to the Academy. Eve, who is in love with Jonathan, a longtime friend, believes his story and helps him evade the police. When they arrive at the boathouse where her father, Commodore Gill, lives, Eve asks him to take Jonathan across the channel to France. Later, while an exhausted Jonathan dozes, Gill points out that the bloodstain was smeared on Charlotte's dress, giving the lie to her story, and suggests that they show the dress to the police to prove Jonathan's innocence. When Eve asks Jonathan about the dress, however, he angrily throws it on the fire. Now Eve proposes to try to learn the truth from Charlotte. Against the advice of her father, Eve returns to London and waits with the crowd outside Charlotte's house. When the police leave, she follows them into a pub. She then pretends to faint, prompting Detective Wilfred Smith to offer his help. Eve quizzes him about the case, but he reveals nothing. He then offers to accompany her home and invites himself to tea with Eve and her mother the following day. Pretending to be a reporter, Eve approaches Nellie and offers her money to take her place as Charlotte's maid. Now posing as Nellie's cousin Doris, Eve learns that Charlotte claims to have ended her relationship with Jonathan, who then killed her husband out of jealousy. Later, she sees Charlotte kiss her friend, Freddie Williams. Eve returns home to meet Smith, whom she has nicknamed "Ordinary" Smith, for tea. Gill also appears unexpectedly and informs Eve that Jonathan has run away. After a few minutes, Eve returns to the theater to help Charlotte dress, leaving Smith behind, and Gill follows soon thereafter. Jonathan sneaks into the theater, and Eve overhears Charlotte tell him disinterestedly that she and Freddie will arrange for him to leave the country. When Jonathan realizes that Charlotte has been pretending to love him, he lies and says that he did not destroy her dress. Eve then contrives to warn Jonathan that the police are searching for him, and he escapes. Later, Eve and Gill return home to find Jonathan waiting for them. He admits that his love for Charlotte was foolish, but his words fall on deaf ears because Eve has begun to fall in love with Smith. Accompanied by Smith, Eve attends a society garden party, where Nellie demands more money from her. Eve decides to tell Smith everything, but Gill resolves to trick Charlotte into a confession by asking a small boy to present her with a doll whose dress is smeared with blood. His ploy upsets Charlotte, but she does not confess. Smith then discovers the truth about Eve's deception and believes that she was only pretending to be in love with him. Eve explains and reassures Smith that her feelings are sincere. Gill then suggests that Eve try to blackmail Charlotte and goad her into confessing. In a conversation that is broadcast to the police, Charlotte admits she was present when Jonathan killed her husband. The police then bring Jonathan into the theater to confront Charlotte, but he again escapes, and Eve, who still believes he is innocent, helps him. Meanwhile, Smith tells Gill that Jonathan was acquitted for an earlier murder when he claimed that he killed in self-defense. While they are hiding, Jonathan admits that he did commit murder at Charlotte's instigation and now knows that she wanted to be available to marry Freddie. Eve begs Jonathan to turn himself in, but when he threatens to kill her, she calmly leads him into a trap and summons the police. When he again attempts to escape, Jonathan is killed by the falling fire curtain.