Local myth holds that Boo eats live squirrels and prowls the streets at night, and the children's perception of him is colored by such tales. In the fall, Dill returns to his family in the North and Scout enters the first grade. Scout and Jem begin to discover mysterious objects, designed to intrigue children, hidden in a tree on the Radley property.
When Tom Robinson, an African-American man, is accused of raping Mayella Ewell, Atticus is appointed as the defense attorney. Mayella and her shiftless father, Bob Ewell, live in abject poverty on the outskirts of town. The family is known as trouble and disliked by townspeople. Despite this, Atticus's defense of Tom is unpopular in the white community, and Scout and Jem find themselves taunted at school due to their father's defense of a black man. Atticus consistently strives to instill moral values in his children, and hopes to counteract the influence of racial prejudice. The children view their father as frustratingly staid and bookish, until he is asked by the sheriff to shoot a rabid dog that is roaming the street. .
After Atticus kills the dog, Scout and Jem learn that their father is renowned as a deadly marksman in Maycomb County, but that he chooses not to use this skill, unless absolutely necessary. Scout's aunt, Alexandra, unexpectedly arrives to reside with the Finch family, announcing it is time someone reined in the children. She makes it her mission to counteract Atticus's liberal influence on the children and to instill ladylike virtues in the tomboyish Scout. The night before the trial of Tom Robinson is to begin, a group of local men threaten a lynching, but Scout inadvertently disrupts their plan when she recognizes the father of a schoolmate in the crowd of would-be lynchers. When the trial begins, Atticus tries to protect his children from the anger and prejudice they would hear; however, Scout, Jem, and Dill sneak into the courtroom and sit in the balcony with the black community.