The book opens with the Finch family's ancestor, Simon Finch, a Cornish Methodist fleeing religious intolerance in England, settling in Alabama, becoming wealthy and, contrary to his religious beliefs, buying several slaves.
The main story takes place during three years of the Great Depression in the fictional "tired old town" of Maycomb, Alabama. It focuses on six-year-old Scout Finch, who lives with her older brother Jem and their widowed father Atticus, a middle-aged lawyer. Jem and Scout befriend a boy named Dill who visits Maycomb to stay with his aunt each summer. The three children are terrified of, and fascinated by, their neighbor, the reclusive "Boo" Radley. The adults of Maycomb are hesitant to talk about Boo and, for many years, few have seen him. The children feed each other's imagination with rumors about his appearance and reasons for remaining hidden, and they fantasize about how to get him out of his house. Following two summers of friendship with Dill, Scout and Jem find that someone is leaving them small gifts in a tree outside the Radley place. Several times, the mysterious Boo makes gestures of affection to the children, but, to their disappointment, never appears in person.
Atticus is appointed by the court to defend Tom Robinson, a black man who has been accused of raping a young white woman, Mayella Ewell. Although many of Maycomb's citizens disapprove, Atticus agrees to defend Tom. Other children taunt Jem and Scout for Atticus' actions, calling him a "nigger-lover". Scout is tempted to stand up for her father's honor by fighting, even though he has told her not to. For his part, Atticus faces a group of men intent on lynching Tom. This danger is averted when Scout, Jem, and Dill shame the mob into dispersing by forcing them to view the situation from Atticus' and Tom's points of view.
Because Atticus does not want them to be present at Tom Robinson's trial, Scout, Jem and Dill watch in secret from the colored