Emma follows the titular character Emma Woodhouse as she grows from an immature young adult who, while well-intentioned, seeks to manipulate and control the lives of others, to a grounded adult who recognizes her own faults and works to improve them. Emma is an intelligent, sociable, and self-assured young woman whose wealthy class status allows her uncommon freedom and power. She is, perhaps, too clever for her own good. Her small town and its inhabitants provide little intellectual stimulation, and Emma resorts to entertaining herself by organizing and directing the lives and romances of her friends. She believes that she has a knack for understanding people’s hidden wants and intentions, and fancies herself an excellent matchmaker. But her attempts to find an upper-class husband for her middle-class protégée Harriet prove to be heartbreaking for Harriet and perhaps even ruinous for her future, and Emma must face the consequences of treating others as puppets rather than human beings. Emma’s character growth is the focal point of the novel, and by the book’s end, she is a much-changed woman.

At the start of the novel, Emma is deeply pleased with herself for having subtly yet successfully matched her beloved governess Miss Taylor with the kind and wealthy Mr. Weston, and she is ready for her next matchmaking project. In the novel’s inciting incident, Emma influences Harriet Smith to reject the marriage proposal of Robert Martin and instead set her sights on the town’s clergyman, Mr. Elton. Emma believes wholeheartedly that Mr. Elton has taken interest in Harriet, despite the warnings of both Mr. George Knightley, who knows that Mr. Elton would never marry below his station, and his brother Mr. John Knightley, who observes that Mr. Elton’s true affections are for Emma, not Harriet. Emma thinks that she knows best when it comes to the lives and feelings of others, and while all evidence points toward proving the Knightleys right, Emma is blinded by her fantasies. The novel’s rising action brings Emma’s hopes crashing down as Mr. Elton proposes to her, which sends Harriet into a depression but does not yet shake Emma’s confidence. It also brings the arrival of Frank Churchill and Jane Fairfax, who further complicate Emma’s assurances of her own powers of perception. 
Frank Churchill is rich, attractive, and amiable, and he and Emma immediately strike up a flirtation. Emma is determined to like Frank, since he is her friend Mr. Weston’s son, and even considers him as a potential partner for herself despite her earlier claims that she would never marry. Just as she previously overlooked Mr. Elton’s smarmy qualities, Emma chooses to overlook Frank’s childish qualities, convincing herself that he is the perfect suitor she always hoped he would be. On the other hand, Mr. Knightley, the novel’s moral epicenter, isn’t shy when it comes to criticizing Frank. Meanwhile, the mystery of Jane Fairfax’s secret admirer appeals to Emma, who believes that she, despite having very little true insight into the situation, knows the truth about the scandal. Once again blinded by her own imagination, Emma fails to see the signs that Frank is Jane’s lover, and that his flirtation with Emma is simply a ruse to shield his controlling aunt from discovering his secret engagement to Jane. The climax of the novel begins when Frank flirts shamelessly with Emma at a social event to make Jane jealous, and Emma, spurred on by the banter, insults her longtime friend Miss Bates. Thus begins Emma’s journey to making amends for her mistakes.

The novel’s climax continues when Frank and Jane’s engagement comes to light, and Emma learns that she has been used by Frank as a diversion tactic. Emma also discovers that Harriet has fallen in love with Mr. Knightley, and believes, despite their large class divide, that he is interested in her as well. Harriet’s admission spurs Emma’s sudden realization that she herself is in love with Mr. Knightley, and she is heartbroken at the thought of him marrying anyone else. At this point, Emma realizes that her schemes to marry Harriet to a wealthy man may have resulted in Emma losing the only man she has ever truly loved, and that her meddling in other people’s lives has only brought pain and confusion to them and herself. In putting all her energy into satisfying the romantic lives of others, Emma has neglected her own heart and needs, and it may be too late to have what she truly wants. Luckily for Emma, Mr. Knightley is not interested in Harriet, and he and Emma both admit their love for one another.

During the novel’s falling action, Frank Churchill sends an apologetic and explanatory letter that details why he hid his engagement and his regret at having involved Emma and the rest of Highbury in his schemes. Now having been the victim of manipulation rather than the perpetrator of it, Emma is sufficiently humbled. She realizes just how little understanding one can have of the inner workings of another person’s heart, and that it is not her place to puppeteer other people’s lives. The happy weddings of Harriet Smith and Robert Martin, Frank Churchill and Jane Fairfax, and finally Emma and Mr. Knightley, show that all is well, and Emma moves into her adulthood having gained maturity, wisdom, and kindness.