Abigail Trent Budell, a wealthy resident of Philadelphia and a generous patron of the arts, hopes to launch the singing career of her young granddaughter Prudence by introducing her to friend and noted musical conductor José Iturbi. Jose auditions Prudence for an upcoming opera and compliments her singing voice, but when he criticizes her style, she angrily storms out of the house. Abigail, whose own mother denied her the opportunity to sing professionally when she was young, is determined to help Prudence realize her dreams. To do so, Abigail finances the construction of an opera house in Philadelphia, and hires Jose to direct the new company. While Abigail begins a radio campaign to publicize the new concert hall, Jose casts Prudence in the company's first opera, opposite tenor Signor Guido Russino Betelli. During rehearsals, Jose realizes that Prudence has trouble looking directly at Betelli when she is singing to him, and tries to solve the problem through coaching. The coaching proves ineffective, however, as Prudence rejects Jose's instructions and complains that Betelli is too fat to look at. A short time later, Prudence meets Johnny Donnetti, a handsome former New York opera star who left the stage to become a truck driver for Artie Geoffrey Glenson's trucking company. While a romance blossoms between Johnny and Prudence, Jose discovers Johnny's singing abilities and introduces him at one of the concerts. After winning a standing ovation from the audience, Johnny is invited to join the company and sing with Prudence and Betelli. Complications soon arise, however, when Betelli objects to the presence of another tenor in the program and tears up his contract. Betelli's departure pleases most of the company, especially Prudence, who immediately asks Jose to replace Betelli with Johnny. Jose grants her request, but Prudence's hope of a continuing romance with Johnny is soon dashed when she discovers that Johnny intends to marry his former sweetheart Mary. Unaware that Johnny is not in love with Mary and that his marriage proposal was a result of a misunderstanding, Prudence grows increasingly despondent and her performance begins to suffer. Confusion ensues when Johnny quits the opera mistakenly believing that Abigail hired him to marry Prudence. Desperate to fill Johnny's role, Jose recalls Betelli, but is disappointed to find that Prudence is still unable to look at him when she sings. Things look bad for the opera until Mary overhears Johnny tell Jose that he does not love his fiancée, and he breaks off the engagement. The success of the opera is ensured only moments before its opening, when Betelli is tricked into quitting, and Johnny agrees to go on in his place. Prudence is delighted to see Johnny back, and the two celebrate their reunion with a kiss.