An Iowa family finds romance and adventure at the yearly state fair.

The members of the Frake family bustle about their Brunswick, Iowa farm, making the final preparations for their annual trip to the state fair. Father Abel, who is entering his prize boar, Blue Boy, in the hog contest, confers with mother Melissa, who is considering adding brandy to her mincemeat entry, while son Wayne practices his ring tossing and daughter Margy frets over her restlessness. Margy's sincere but boring beau, Harry Ware, tells Margy that he cannot accompany her to the fair, and when he proposes, she stalls by promising him an answer upon her return. Wayne's childhood sweetheart, Eleanor, cannot attend either, and both Wayne and Margy are melancholy as they leave. After the Frakes set up a temporary home in a nearby trailer park, Wayne goes to the fairgrounds, where he attempts to humiliate the ring toss barker, whose unfair tactics cost Wayne eight dollars the previous year. The barker threatens to call the police, but a beautiful young woman, claiming to be the police chief's daughter, persuades him to return Wayne's money. Wayne is enchanted by the woman, but she states that she is late for an appointment and leaves. Meanwhile, Margy makes the acquaintance of reporter Pat Gilbert, who is covering the fair for the Des Moines Register , and the couple spend a happy day together. That night, Margy and Pat again meet at the fairgrounds, and Wayne discovers that his mystery woman is singer Emily Edwards. Wayne persuades Emily to dance with him, and she soon returns his affections. The next day, as Abel broods over Blue Boy, who has become enamoured of a sow named Esmerelda, Melissa attends the judging of the pickles and mincemeat. Despite competition from a longtime rival, Melissa wins a prize for pickles and a special award for her mincemeat, to which both she and Abel secretly added brandy. In the evening, Wayne attends a birthday party given by Emily for Marty, a fellow singer, and is angered by Marty's snobbish insinuations about him. Emily calms Wayne down, and the couple spend the night declaring their love, as do Margy and Pat. Knowing that he is not the sort of fellow to settle down, Pat warns Margy that he is no good for her, but she vows that she will marry no one but him. Wayne and Margy arrive home at dawn, and that afternoon at the Swine Pavillion, Abel is triumphant when Blue Boy wins his contest, despite his continued lovesickness for Esmeralda. In the evening, Pat receives word that he has been offered an important job in Chicago and leaves without saying goodbye to Margy. The young woman is crushed by Pat's disappearance, and Wayne's romance also ends when he learns that Emily is married, although she is separated from her husband. The next day, after the Frakes return to their farm, Abel tries to collect on a wager he made with his pessimistic friend, Dave Miller, that the family members would all have a good time. Miller is reluctant to pay because of Wayne and Margy's sad faces, but when Margy receives a call from Pat, who says that he is driving to Brunswick to take her with him to Chicago, she declares that this year's fair was the best ever. Soon after Margy has dashed off, Wayne and Eleanor, who have reunited, cuddle as they drive past Margy and Pat embracing on the side of the road.