To Kill a Mockingbird tells the story of the young narrator’s passage from innocence to experience when her father confronts the racist justice system of the rural, Depression-era South. In witnessing the trial of Tom Robinson, a Black man unfairly accused of rape, Scout, the narrator, gains insight into her town, her family, and herself. Several incidents in the novel force Scout to confront her beliefs, most significantly when Tom is convicted despite his clear innocence. Scout faces her own prejudices through her encounters with Boo Radley, a mysterious shut-in whom Scout initially considers a frightening ghost-like creature. The novel’s resolution comes when Boo rescues Scout and her brother and Scout realizes Boo is a fully human, noble being. At the same time, Scout undergoes an inevitable disillusionment as she is exposed to the reality of human nature. The entrenched racism of her town, the unfair conviction and murder of Tom Robinson, and the malice of Bob Ewell all force Scout to acknowledge social inequality and the darker aspects of humanity. Throughout the book, her father, Atticus, represents morality and justice, but as Scout becomes more sensitive to those around her, she sees the effect of his struggle to stay purely good in a compromised world.

The book opens with a framing device that references Scout’s brother, Jem, breaking his arm when he was thirteen. Scout says she will explain the events leading up to that injury, but is uncertain where to start, raising the question of the past’s influence on the present. After tracing her family’s history and describing how her father, Atticus, came to be the attorney for Maycomb, Alabama, she picks up her narrative almost three years before the incident, when she is “almost six” and Jem is “nearly ten.” She presents Maycomb as a sleepy, impoverished town still rooted in the rhythms and rituals of the past. Her loving characterization of the town depicts it as an ideal place to be a child, where Scout and her brother play in the street all day long during the summer. These opening scenes of safety and innocence are later contrasted with her more mature, nuanced descriptions of the town’s darker aspects and the price of its attachment to the past.

In the following chapters, Scout recounts a series of amusing stories introducing us to the main characters in the book and establishing the town’s social order. At the urging of their friend, Dill, Scout and Jem try to coax their mysterious neighbor, Boo Radley, out of his house. Boo has lived as a prisoner in his own home after getting into trouble as a teen; when he was in his thirties he stabbed his father in the leg with a pair of scissors. He has become a figure of local gossip and speculation, and the children are terrified and fascinated by his seemingly monstrous, ghostly nature. When Scout enters school, we meet Walter Cunningham, the son of a poor but proud family of farmers. When Walter comes to lunch at Scout’s house, Scout is reprimanded for mocking his table manners, one of her first lessons in empathy. Another child at school, Burris Ewell, introduces us to the Ewell family, who will figure prominently later in the book. The Ewells are a mean, antisocial clan who rely on government assistance and only send their children to school one day a year, to avoid the truant officer. Burris threatens the teacher with violence, foreshadowing the violent attack by his father later in the book. Burris’s father, Bob, represents the racism and violent past of the South, and is the book’s antagonist.

The inciting incident in To Kill a Mockingbird occurs in chapter nine, when Scout learns from other children that her father is defending a Black man, Tom Robinson, who has been charged with assaulting Mayella Ewell, a white woman. When Scout and Jem’s neighbor, Mrs. Dubose, verbally harasses the children about their father’s work, Jem retaliates by destroying her garden. As punishment, he is required to read to Mrs. Dubose, and Atticus reveals that she is a morphine addict determined to overcome her addiction before she dies. This episode further develops the idea of gaining empathy for others by understanding their situations. It also introduces the concept of bravery as adhering to a principle at great personal cost. Atticus’s admiration of Mrs. Dubose’s determination to die “free” is later echoed in Scout’s admiration of his conviction to his values even at the potential price of his personal safety. This conviction is displayed when he spends the night guarding Tom’s jail cell. The white community in Maycomb is outraged and attempts to lynch Tom, but Scout saves Tom and Atticus by interrupting the attempted lynching and inadvertently reminding the mob of their own children. Although she is central to this event, she does not fully understand its ramifications. This combination of naïveté and attentive witnessing characterizes Scout’s narration throughout the entire book.

The climax of the book occurs at the conclusion of Tom’s trial and the delivery of the jury’s verdict. At the trial, Scout and Jem sneak in and sit with the Black spectators, even though Atticus forbade them from attending. In his defense, Atticus establishes that Tom was physically unable to attack Mayella, and suggests that in fact Mayella approached Tom for sex and Mayella’s father, Bob, beat her when he saw them together. In questioning Mayella about her family’s circumstances, Atticus paints a bleaker, more troubling portrait of Maycomb than Scout’s earlier descriptions of the town, revealing the economic disparity between relatively comfortable families like the Finches and the impoverished Ewells. Despite Atticus’s defense and the judge’s implied belief in Tom’s innocence, the jury convicts Tom in a climactic reversal of our expectations that good will triumph over evil. Scout is shocked by the verdict, and the contrast between her surprise and her father’s resignation reveals how many illusions about the world Scout still has to lose. Later, Tom is shot to death while attempting to escape prison. This event underscores how thoroughly the justice system has failed Tom and the Black community of Maycomb. Both Scout and Jem must reconcile their new understanding of the world with their father’s idealism and high moral standards.

The falling action of the book takes place on Halloween, a few months after the trial. Despite Tom’s conviction and death, Bob Ewell feels humiliated by the events of the trial, and seeks revenge on Tom’s widow as well as the judge. Following the Halloween pageant, Bob attacks Scout and Jem, breaking Jem’s arm. Boo Radley rescues them by killing Bob with his own knife. The re-emergence of Boo shows how community can be a powerful protective force, softening the social criticism of the trial sequence. However, Boo’s reclusiveness and Atticus’s decision to say Bob Ewell fell on his own knife also demonstrate that these two men still perceive community as a risky, potentially destructive entity. Boo’s kindness somewhat restores Scout’s faith in humanity, and her assertion that “nothin’s real scary except in books” suggests that she feels prepared to face the world with her new, adult understanding of its complexities. The resolution of the novel suggests that humanity will be all right as long as we remember to see each other as individuals and empathize with their perspectives. While the ending implies that Scout has made a significant and beneficial transformation over the course of the novel, Lee leaves the larger problem of the institutionalized racism and economic inequality of the South unresolved.