The Ingalls and Olesens travel to the annual fair in Mankato. Each of the members of the family get caught up in a number of adventures, but two main storylines take place throughout the episode:
* Patrick, a carnival worker and Mary's boyfriend, and his boss, Cass (a balloonist and suave ladies man) vie for Mary's attention. Cass uses his position to try to win the eldest Ingalls daughter's love by showing her around. He saddles Patrick with extra duties to keep him away from Mary.
* A pickpocket ever-so-cleverly swipes the billfolds, purses, etc., from unsuspecting fair goers, and inserting their contents into a large suitcase. All the while, he's unaware that a woman is trailing him and also looking to work the crowd.
Interspersed in all this are a number of adventures, including:
* Charles and Nels entering a jackass riding contest, which Nels wins. He collects $50, but the whole concept disgusts his wife.
* Caroline's homemade pickles takes top honors, soundly beating Mrs. Olesens' entry, furthering her disgust.
* Laura loses 50 cents to a barker in the Shell Game, so she makes it up by sitting in a dunk tank. Nellie walks by, sees her rival sitting inside and, hoping to gain upmanship, spends her money to dunk Laura. Nellie fails miserably, but then Laura offers to split her $1 earnings with her if she sits in the tank. A young man dunks Nellie immediately!
Back to the storyline about Mary and Cass, Charles has asked her and Laura to keep an eye on Carrie and let her ride the carousel. However, Mary and Laura would rather do other things than watch their younger sister.
For Mary, it means riding with Cass in a hot air balloon, despite Charles' orders not to. Charles is upset, but when Mary tells him how wonderful the view is and that the balloon works easily, he calms down.
Later, Laura is asked to watch Carrie, but when Bandit runs off to mate with another dog, Carrie has to wait in line alone, without any money.
Eventually, Carrie gets tired and finds somewhere to nap. This, while Patrick finally loses patience with Cass, who is about to capture Mary's heart. So, he sets the hot air balloon in flight, unaware that Carrie has found her napping place inside the basket.
Everybody is awed at the beauty of the balloon, but Charles is alarmed when he sees Carrie waving bye-bye in the basket ... alone and obviously unable to bring the balloon down. Charles immediately summons a volunteer fire department (which had been demonstrating modern fire-fighting equipment at the fair), and they chase the balloon out into the countryside, Patrick clinging to the safety rope for dear life.
Eventually, Charles gets the firefighters to extinguish the burner, and the balloon lands safely. Patrick immediately confesses his actions and apologizes, and Mary, seeing Cass for who he really is, tells the balloonist to get lost.
In the wrap-up, the pickpocket and his lady friend sit down to discuss their ill-gotten goods. The pickpocket turns his back for a moment, only for the woman to make off with everything!