Within a week, Hugo Meyerheld, the old-fashioned music director of Sunrise Studios, must find a young composer to write a modern score for one of Sunrise's pictures, or be fired by studio head Saul Dana. When Angela Jones, his devoted secretary, insists on taking Hugo to hear Ding Dong Williams, a jazz clarinetist, Hugo is leery, as Angela's "ideas" always lead to trouble. Despite his initial apprehensions, however, Hugo discovers that the unassuming Ding Dong is an excellent jazz composer. Ding Dong refuses their job offer, however, until Angela promises to introduce him to Steve Moore, his favorite Western singing star. Soon after their arrival at the studios, the starstruck Ding Dong reveals to Angela that he cannot read or write music and consequently never plays any of his compositions twice. Although a shocked Angela tries to convince him not to tell Hugo the truth, Ding Dong bares his soul to the conductor, who then faints with dread. Determined to save her boss, Angela takes Ding Dong to see musical arrangers Zing and Zang, and they agree to copy down Ding Dong's music as he composes it. When Ding Dong then confesses that he only composes when he is sad, Angela, Zing and Zang try in vain to depress him. In desperation, Zing and Zang lie to Ding Dong that Stardust, Steve Moore's movie horse, is seriously injured, but their plan backfires when Ding Dong's subsequent plaintive clarinet playing is heard by Steve and Vanessa Page, Steve's former co-star and girl friend. Vanessa, who has recently made the move from Westerns to "features," is still in love with Steve and is jealous when he reveals that he is dating his new co-star. Hoping to make Steve jealous, she demands that Ding Dong accompany her to the Club Creon that night. When Angela learns of Ding Dong's date, she grows despondent and is upset the next day when gossip columnist Laura Cooper writes an item about his burgeoning "romance" with Vanessa. With time running out on Hugo, however, Angela decides to be indifferent to Ding Dong, hoping that her seeming lack of interest will make him depressed, and tells him that she has a date with Steve that night. Knowing that Vanessa and Ding Dong will be passing by her apartment, Angela steals Stardust from the studio and fashions a Steve Moore "dummy" to dance with her in front of her living room window. As hoped, a saddened Ding Dong begins composing on his clarinet, while Vanessa, furious with jealousy, confronts Angela, who is recording Ding Dong's playing on a portable recording machine. Soon Ding Dong's music causes the neighbors to call the police, and a full-scale brawl ensues. All appears lost until the next day when Dana, who has fired Hugo, Angela and Ding Dong, hears the musician improvising with the studio orchestra. Impressed by Ding Dong's composition, Dana rehires him along with a relieved Angela and Hugo.