Musicians Scat Sweeney, Bing Crosby, and Hot Lips Barton, Bob Hope, are refugees from a swing quintet that has disbanded. Lucia Maria de Andrade, Dorothy Lamour, a glamorous nightclub singer, welcomes them as backing musicians on clarinet and trumpet. They travel the United States in search of steady work, dodging romantic entanglements as they go, and eventually stow away aboard a ship headed for Rio to escape yet another pursuit of romance.
Onboard, they run into Lucia in trouble and, after a tense moment, are handed over to the ship's captain, Captain Harmon, Stanley Andrews. Unbeknownst to Scat and Hot Lips, Lucia is being hypnotized by her crooked guardian, Catherine Vail, Gale Sondergaard, who plans to marry Lucia off to her brother in order to seize control of Lucia’s papers and the power they represent. A backstage-style deception unfolds as a nightclub owner hires Scat and Hot Lips to headline, but he expects the full swing quintet for the show.
To keep the act alive, Scat and Hot Lips recruit three local musicians (the Wiere Brothers) and coach them with a few phrases in jive talk, hoping to fool the owner into thinking they’re still the complete quintet. Yet the danger intensifies as Vail’s plot thickens: she hypnotizes the two leads and tries to force them into a fatal duel, a gambit that backfires and exposes her scheme. The stakes rise as Scat and Hot Lips realize they must act quickly to protect Lucia and intercept the crooked arrangement before it’s too late.
In a decisive race against time, the pair rush to derail the wedding and seize the papers that could grant Vail the control she seeks. Scat reads the documents, and in a moment of defiant resolve, tears them up and locks eyes with the audience, delivering a memorable meta-statement: > The world must never know. This choice underscores the film’s blend of musical comedy and melodrama, where danger and wit collide on a sunlit, fast-paced journey.
The tension shifts as it becomes clear that Lucia’s heart leans toward Hot Lips rather than Scat, though a peek through a keyhole hints that Hot Lips continues to exercise hypnotic sway over her. The movie builds its comic-energy chase toward a dramatic culmination, punctuated by a cameo from Hope’s frequent sidekick Jerry Colonna, who arrives in a cavalry-charge moment aimed at rescuing Bing and Bob. The scene loops back to the idea that the rescue arrives just as the action softens, with Colonna quipping about the near-miss: “Whaddaya know? We never quite made it. Exciting, though, wasn't it?”
