A group of young performers attempt to sneak out of Mrs. Murphy's Theatrical Boarding House, as they are unable to pay their back rent. After their landlady stops them, fellow tenant Marvo the Great, a magician, pays all their back rent by selling his clothes. The out-of-work performers then follow Marvo to radio station WECA to see his former assistant, singer Anne Payne, who is performing with the Andrews Sisters and Woody Herman and His Orchestra as part of the Glitter Toothpaste radio show. Marvo later meets with Anne at her Brynhurst estate, and she agrees to let the magician and his friends live with her. Anne's wealthy next-door neighbor, Sue Courtney, wanders over to the singer's home and asks if she can sing with the young performers. Back at the Courtney estate, meanwhile, J. P. and Agatha Courtney, Sue's uncle and aunt and owners of All-American Foods, meet with their advertising counselor, Bob J. Riley. After Agatha insists that their new radio show consist only of classical music, Sue offers to help Bob convert her aunt to "swing" music if he agrees to help out the unemployed performers next door. Upon hearing the neighbors perform, Bob is immediately attracted to Anne and wants to put together a radio show with all of her friends. Unfortunately, Agatha has already decided to engage Professor Bistell to conduct a "classic hour." Knowing her uncle's weakness for magic, Sue agrees to have Marvo teach J. P. the tricks of the trade if he agrees to help stop Agatha's classical show. When Bob fails to keep his appointment with Bistell, the professor signs an exclusive contract with rival advertising agent K. D. Reynolds. Meanwhile, Bob courts Anne, which gives Sue similar ideas about young performer Tommy. In order to circumvent Reynolds' proposed show, Sue auditions for Reynolds as a child opera singer under the alias Priscilla Winterfield. She wins the role, and when Bob offers Agatha his "swing" show, she reluctantly signs with Reynolds. The first new "classical hour" is broadcast from the Courtney estate, and after sabotaging Bistell's first solo, Sue takes the stage with the Andrews Sisters and Woody Herman's orchestra to perform "swing." Agatha is immediately won over, and the entire entourage joins together to sing the grand finale.