Enter Sir John

Young actress Martella Baring is convicted of the murder of Edna Druce, the wife of the acting company's manager. The charmming and clever Sir John Saumarez, himself an actor and the manager of an acting company, attends the trial and becomes convinced of Martella's innocence. He enlists the help of his stage manager and the stage manager's wife, and Sir John proceeds to prove Martella's innocence and save her from hanging for a crime she didn't commit.