Andy is buying a car and finds himself juggling three girls before the coming dance.
Judge James Hardy (Lewis Stone) sentences Jimmy (Gene Reynolds) to 90 hours work for wrecking a car and then arranges a case to get his wife a cook. Andy Hardy (Mickey Rooney) makes a down-payment on a car and must pay $8 by the 23rd; but Polly Benedict (Ann Rutherford) tells him she can't go to the dance, because she is going away. James Hardy won't give Andy money for the car. Betsy Booth (Judy Garland) arrives to stay with her grandma next door and meets James Hardy. Marian Hardy (Cecelia Parker) cries and tells her father she is through with men. Mrs. Emily Hardy (Fay Holden) gets a telegram that her mother had a stroke and leaves with Aunt Millie. Marian prepares breakfast, but her coffee is terrible. James sends Andy with preserves to meet Betsy. Beezy (George P. Breakston) tells Andy he is going away and promises him $8 for going with Cynthia. When Andy asks Cynthia Potter (Lana Turner) to the dance, she kisses him. Beezy complains about the kiss.
Betsy has her chauffeur wash the car for Andy. Cynthia sees Andy buying a soda for Betsy, but Andy arranges to play tennis with Cynthia. Andy explains to Betsy how he is dating Cynthia to buy a car, and Betsy offers $8. Cynthia does not swim, but she likes kissing Andy. Betsy gives Andy a hood ornament. After Andy runs off, Betsy sings "In Between" because she is not yet grown up. Andy gets a telegram that Polly is returning for the dance. When Andy reads the letter from Beezy that the deal is off, Betsy offers to pawn her fur jacket. Andy tells his father that he has two girl-friends and needs $8 for the car. The judge tells Andy he is saving it for college. The judge wants to get a message to Emily, and Andy arranges for Jimmy to send it by ham radio. Judge Hardy gets the car for Andy. Betsy asks Andy what he is going to do about Cynthia and Polly. Betsy shows Cynthia a junky car as Andy's, and Cynthia calls Andy that she won't go with him. Andy takes Betsy to see Polly, who is jealous, calls Andy a gigolo, and says she is going with someone else.
Betsy shows herself in a pretty dress to Andy, and he takes her in his car to the dance. Polly's date Dennis (Don Castle) recognizes Betsy from New York and asks her to sing "It Never Rains But What It Pours." Then Betsy sings "Meet the Beat of My Heart." Betsy and Andy lead the grand parade. Andy gives Betsy a Christmas present, and Emily arrives home. Polly's cousin Dennis goes out with Marian, and Betsy gets Polly and Andy back together. In the final scene Polly makes Andy happy with a kiss.
This realistic domestic comedy portrays the difficult early stages of teen romance and parental concern.