Mrs. Chester's fair (see Chapter 29) is a small, select affair; only the most genteel girls in the area are being asked to take charge of tables. That includes Amy, but not Jo, who tends to be clumsy.
Amy is put in charge of the art table, since she made many of the things that are on it for sale.
The day before the fair, as they are setting up, Mrs. Chester asks Amy to let May be in charge of the art table instead. May Chester has been jealous of Amy in general, and the Chesters are also offended because of Jo's rude imitation of May Chester when she visited the Lambs (see Chapter 29).
Amy is hurt and doesn't understand what's going on. She offers to withdraw from the fair entirely, but Mrs. Chester starts to feel bad and insists that she take the flower table. Amy agrees.
May starts to feel guilty, because Amy has spent so much time and energy arranging the art table and making things for it. She offers to let Amy take her own things to the flower table. Amy misunderstands and thinks that May is scorning her wares; she sweeps them into her apron and walks away.
Amy spends the last few hours of her evening trying to get the flower table in shape. Before she came over, it was being run by some of the little girls, and it's pretty disastrous.
When Amy goes home that evening, her family are indignant about the snub that she's received. Her sisters think she should withdraw from the fair, but Amy and her mother agree that it's better to turn the other cheek.
The next morning, when Amy is putting the finishing touches on her table, she comes across an illustration with the slogan "love thy neighbor as thyself." She looks over at May at the art table and notices how empty the table seems without her wares on it.
Amy overhears some of the other girls saying that she was selfish and rude to take her wares away from the art table. Between this criticism and the "love thy neighbor" reminder, she goes over and offers May the wares again. May gratefully accepts.
The atmosphere is cleared by Amy's kindness; things go OK with the flower table from here on out. However, the first day of the fair drags for her; the flower table isn't very popular, because it's summer and people can just pick flowers. Meanwhile, people crowd around May at the art table.
Amy goes home in the evening, worn out and depressed. Her family sympathizes with her.
Laurie arrives home for the weekend from college. Jo tells him what has been happening. Laurie arranges to donate some of the exotic flowers from his grandfather's garden to Amy's table for tomorrow. He also arranges for a group of young men he knows from college to go to the fair and buy things from Amy. (Presumably the fair is raising money for charity.)
The next day, the fair is entirely different. Amy's table is much more popular, due to the flowers that Laurie donated and the presence of Jo, laughing and chatting.
At one point, Jo scopes out the rest of the fair. She goes to see May at the art table, and May is polite and seems sorry for her pettiness earlier. Jo thinks May is hiding Amy's wares, because they're nowhere to be seen, but May explains that Amy's things have sold out.
Jo returns to the flower table and tells everyone about May's change of heart. Laurie orders his college friends to go and buy the rest of the stuff from May's table, including the vases that May herself painted.
Aunt Carrol and Mrs. March are also attending the fair. Aunt Carrol learns about what happened and about Amy's good behavior. She says something to Mrs. March, who smiles.
That evening, Amy's sisters praise her exemplary behavior.
A week later, Mrs. March receives a letter from Aunt Carrol. The Carrol family is going to Europe, and they want to take Amy with them!
Jo is very disappointed; she always thought that she would get to go to Europe as Aunt March's companion. Her mother tells her that the letter explains the aunts' change of heart: since Jo said that she hates favors and can't learn French, and since Amy is more polite and cultured, they're taking Amy.
When Amy comes home and learns about her opportunity, she is very excited. She considers it a working holiday – she's going to try and make her way as an artist in Rome.
The preparations for Amy's departure are rapid. At the last minute, before her family say goodbye to her on board the ship, she clings to Laurie. She asks Laurie to take care of her family while she's gone. Laurie promises to do so – and to come see her in Europe if she ever needs him.