Out of work swing band maneuvers a gig working for a political campaign, by drawing in and entertaining prospective voters at rallies. The candidate is really a stooge for a corrupt political machine, which discovers the band's handsome and appealing singer would make a better stooge. Meanwhile, romance blossoms between the band's singers. When election day approaches, the band's singer wants out of the campaign, but the machine threatens to smear him and his pals in the band if he quits.

Broadway partners Vicky Lane and Dan Christy have a tiff over Christy's womanizing. Jealous Vicky takes up with her old flame and former dance partner, Victor Price, and Dan's career takes a nosedive. In hopes of rekindling their romance and getting Vicky back on the boards with him, Dan follows her to a ritzy resort in the Canadian Rockies, where she and Victor are about to open their new act. But things get complicated when Dan wakes after a bender to find that he's hired an outlandish Latin secretary, Rosita Murphy, which makes Vicky think he's just up to his old tricks again.

Katharine Hilliard, mousy dean of a stuffy music school, meets and is insulted by swing band leader Barry Clayton on a train. To "show" him she takes a friend's advice, removes her glasses, and puts on a designer gown. Naturally, she becomes gorgeous. Soon, both Barry and crooner Jimmy Hale are after her, and she finds herself in the midst of triangles and misunderstandings.

A young Irishwoman comes to the United States to live and work with her mother as a cleaning lady at Carnegie Hall. She becomes attached to the place as the people she meets there gradually shape her life. The film also includes a variety of performances from some of the foremost musical artists of the times: conductors Bruno Walter & Leopold Stokowski, solists Arthur Rubinstein & Jascha Haifetz, singers Lily Pons & Jan Peerce and bandleader Vaughn Monroe among many others.