Sal comes to the Barbary Coast from New England to find out who murdered her brother. She gets a job signing in Dude's saloon, falls in love with Dude, then wonders if he might be involved in the murder.

In his last film assignment, portly Walter Connolly fills the title role (in more ways than one) in The Great Victor Herbert. Very little of Herbert's life story is incorporated in the screenplay (a closing title actually apologizes for the film's paucity of cold hard facts); instead, the writers allow the famed composer's works to speak for themselves. In the tradition of one of his own operettas, Herbert spends most of his time patching up the shaky marriage between tenor John Ramsey (Allan Jones) and Louise Hall (Mary Martin). Many of Herbert's most famous compositions are well in evidence, including "Ah! Sweet Mystery of Life", "March of the Toys" and "Kiss Me Again", the latter performed con brio by teenaged coloratura Susanna Foster. Evidently, the producers were able to secure the film rights for the Herbert songs, but not for the stage productions in which they appeared, which may explain such bizarre interpolations as having a song from Naughty Marietta.

Two Bowery vaudevillians find success in producing shows on Broadway, but when one of them suddenly departs to work for a beautiful woman, a feud erupts.

Dr. Hohner, theatre physician at the Vienna Royal Theatre, murders his mistress, the star soprano when his jealousy drives him to the point of mad obsession. Ten years later, another young singer reminds Hohner of the late diva and his old mania kicks in. Hohner wants to prevent her from singing for anyone but him, even if it means silencing her forever.