One evening, medical student Joe Davis, Jr., visits his entertainer father at impresario Billy Rose's famous Diamond Horseshoe nightclub in New York City. After the show, Davis, Sr. is squabbling with singer Bonnie Collins, with whom he has a bitter rivalry, when he spots Joey. Although Davis is delighted to see Joey, he is disappointed when his son announces that he is giving up his studies to enter show business. Davis tries to explain the many difficulties of theater life, and in order to keep an eye on Joey, immediately arranges for him to work as an assistant to stage manager Blinkie Miller. Distraught over her argument with Davis, Bonnie then faints backstage and Blinkie asks Joey to examine her. Believing that Joey is a doctor, Bonnie is not perturbed when she discovers that he loosened her tight costume while she was unconscious. When she learns that he is Blinkie's new assistant, however, Bonnie assumes that he is not a doctor and slaps him for being fresh. A week passes as Joey learns his job and tries to date Bonnie, who gives him the cold shoulder. When Blinkie hears Joey sing, though, he realizes that Joey has real talent and offers to take him to the Footlight Club, where he can sing with the band. After the show at the Diamond Horseshoe, Joey and Blinkie leave for their evening out, while Bonnie returns home, where her roommate and fellow performer, Claire Williams, is packing her belongings. Claire explains that Davis, to whom she is engaged, has ended their relationship so that he can devote himself exclusively to Joey. Knowing that Bonnie covets her mink coat, Claire offers to give it to her if she will get Joey to leave town by pretending to fall in love with him and then dump him. Reluctantly agreeing, Bonnie accompanies Claire to the Footlight Club, where she listens to Joey sing and begins to charm him. Impressed by Joey's good nature, Bonnie has second thoughts about tricking him, but a dream about fur coats convinces her to continue. Bonnie goes with Joey on a picnic the next day, and when she sighs over luxurious items such as furs and yachts, Joey relates his theory that women who want fur coats are sublimating their desire for a husband. Bonnie is infuriated by Joey's psychology lessons, but falls in love with him as they spend more time together. Joey does not tell Davis about the romance, but he discovers it himself when he finds the couple in a nightclub. Bonnie leaves so that Joey can talk to his father, and Davis advises him to break up with Bonnie, whom he considers to be a gold digger. Joey storms out and Davis then confronts Bonnie. She states that she loves Joey and that Davis should not try to push his son into medicine if he truly wants to be a singer, but when Joey saves the life of a man suffering from insulin shock, Bonnie realizes that Davis is right about where Joey's true talent lies. Hoping to encourage Joey to return to medical school, Bonnie turns down his marriage proposal, telling him that he will have to be a success in show business before she will marry him. When he sees her toss away Claire's mink coat, however, he realizes that she truly loves him. They are soon married, and a furious Davis demands that Bonnie be fired from the Diamond Horseshoe. Six months pass as Joey tries unsuccessfully to break into show business. Concerned, Bonnie consults his psychology textbook and tells him that his attempt to become a singer is an unconscious effort to prove himself to his father. Joey finally admits that he misses medicine, and when he receives a favorable response to his most recent audition, Bonnie tells him that if he persists with show business instead of returning to school, he will do it without her. Another six months pass, and back at the Diamond Horseshoe, Davis complains to Blinkie about Bonnie's replacement, just as he used to complain about Bonnie. Blinkie then takes Davis to a nightclub to hear a "new" singer, and has to stop Davis from walking out when he recognizes Bonnie. Blinkie explains that Bonnie has been working night and day to support Joey, who has begun his residency at a nearby hospital. Touched by Bonnie's devotion to Joey, Davis quits the Diamond Horseshoe and arranges for Bonnie to be rehired. On Bonnie's opening night, Blinkie schemes to have Davis replace the new leading man during the finale. Davis' sincere apology wins Bonnie over, and as they sing together, they are joined onstage by Joey and Claire.
