For a three-act plot analysis, put on your screenwriter’s hat. Moviemakers know the formula well: at the end of Act One, the main character is drawn in completely to a conflict. During Act Two, she is farthest away from her goals. At the end of Act Three, the story is resolved.
Act I
Carol Kennicott graduates from college with big dreams of changing the world. But that all goes south when she marries Dr. Will Kennicott and moves with him to the dull town of Gopher Prairie. Carol tries to change the town to suit her ambitions, but she quickly finds that the town is much more interested in changing her and making her into a quiet housewife. Carol tries all sorts of sneaky ways to change the townsfolk without them even realizing it—but none of her schemes work.
Act II
Carol feels deeply dissatisfied with her life in Gopher Prairie, but she also feels stuck because now she has a baby son named Hugh. Carol spends most of her time hanging out in nature with Hugh. One day, she meets a tailor's assistant named Erik Valbourg. Like Carol, Erik has grand ambitions. The two have an emotional affair, but the whole thing ends when Will finds out about it and catches them together. Erik leaves town, and Carol is crushed to realize that he doesn't have the talent to make good on any of his big dreams.
Act III
With Erik gone, Carol realizes that she'll never be happy in Gopher Prairie. So she takes her son Hugh and moves to Washington, D.C. She lives there for two years and works in an office building. The change is pretty good at first, but Carol eventually sees that she'll be dissatisfied no matter where she is. She moves back to Gopher Prairie, hoping that her new daughter will have a better chance at a happy life than Carol herself did.