In Las Vegas, as band leader Louis Prima auditions female vocalists, Father Burton and parishioner Dorothy Spencer come to ask him to perform at their local church bazaar to raise money for a summer camp program. After Prima's manager, Marty Moran, brusquely informs them that Prima is busy on the day of the bazaar, Dorothy, angry at getting the "brush off," confronts Prima with her request. When Marty rudely dismisses her once again, Dorothy waits in the lobby for the audition to end. After having run through a disappointing roster of singers, Prima apologizes to Dorothy for Marty's behavior and agrees to entertain at the bazaar. Bolstered by Prima's appearance, the bazaar raises over $3,000 for the summer camp. In gratitude, Dorothy invites Prima to dinner, during which she introduces him to her devoted young brother Buzz. When a neighbor drops by to ask Dorothy to babysit, Dorothy sings the infant to sleep, impressing Prima with her sweet voice. While washing the dishes, Dorothy hums a tune, prompting Prima to offer her the vocalist job, but she refuses. The next day, when Dorothy goes to the theater to ask Prima to join the church fund-raising committee, Marty insists that she sing before Prima gives her his answer. When Prima begins to coach Dorothy during her audition, the band breaks into laughter and Prima realizes that they have created an irresistible comedy routine. As Dorothy achieves prominence with the band, Buzz begins to feel neglected. One night, Buzz sees Prima kiss Dorothy and reacts with a jealous tantrum. Consequently, when Prima proposes to Dorothy, she turns him down and announces that she is leaving the group to spend more time with Buzz. When Prima asks Father Burton for advice, the priest suggests that he try to make friends with Buzz by taking him on a hike. After Prima enlists the band to join them, Buzz begins to reconsider his opinion of Prima. As they hike up the mountain trail to an old resort, they discover that a fence has been erected to block their path. When Buzz wistfully gazes past the fence and describes the pond and other facilities at the resort, Prima decides to lease the land and turn it into a year-round camp for the children. Through a series of fund raisers, Prima and the others raise the $30,000 needed to lease the resort, and after they exceed their goal, Dorothy finally accepts Prima's proposal.