After a stylized opening credit sequence, a camera descends on the languid, small Southern town of Maycomb, Alabama. An adult version of Jean Louise “Scout” Finch narrates the film’s events, which are told from six-year-old Scout’s point of view in the early 1930s, at the peak of the Great Depression. The adult Scout briefly recalls her upbringing in Maycomb, remarking, “The day [in Maycomb] was 24 hours long, but it seemed longer. There was no hurry, for there was nowhere to go and nothin' to buy...and no money to buy it with. Although Maycomb County had recently been told that it had nothin' to fear but fear itself...That summer, I was six years old.”
We then see a poor farmer, Walter Cunningham, deliver a crokersack full of hickory nuts to one of the town’s defense lawyers and Scout’s father, Atticus, as part of entailment for Atticus’s legal work. After an ashamed and embarrassed Walter leaves, Scout inquires about her family’s socioeconomic status and how they compare to the Cunningham family. Atticus tells Scout that they are poor, but not as poor as Cunninghams, whose livelihoods were shaken by the Depression.
In the same scene, Jem—Scout’s older brother—looks down from a treehouse and spots a young boy crouching among the plants. The young boy soon introduces himself to Scout and Jem as Charles Baker “Dill” Harris, who is visiting his aunt, one of Finch’s neighbors, Miss Stephanie Crawford, for two weeks in Maycomb. Dill is eccentric and acts beyond his years, but he, Scout, and Jem become fast friends and spend their summer days playing games, hanging out in the treehouse, and fantasizing about the nearby house which harbors Maycomb’s pariah—Arthur “Boo” Radley. Equally terrified and intrigued by the creaky Radley house, the three children believe in the gossipy story that a cruel Mr. Radley locked up his mentally unstable and troublesome son, Boo, after Boo supposedly stabbed him in the legs with scissors.
One night, Atticus overhears a poignant conversation between Jem and Scout. Scout asks Jem whether their deceased mother was pretty, if they love her, and if he misses her, as Scout was only two years old when she passed and therefore has no real memories of her. Then, a local judge, Judge Taylor, approaches Atticus and informs him that the grand jury will soon charge Tom Robinson, a black man accused of raping a white woman. Judge Taylor asks Atticus if he would defend Tom in court, and Atticus, a deeply moral man, agrees to “take the case.”
Time passes and summer ends. Scout begins school and fights with Walter Cunningham Jr; Scout attempted to explain why the poverty-stricken Walter could not afford lunch, but her teacher “got sore” at her, and Scout projects her frustration onto innocent Walter. Jem stops the fight, apologizes for Scout’s irrational behavior, and invites Walter over for dinner.
During dinner at the Finch household, Jem asks Walter if he has a gun of his own, and Walter says he does. Atticus then shares his own experiences with a gun as a young boy; he explains that his father allowed him to shoot and kill most birds, with the memorable exception of a mockingbird—a harmless songbird that only exists to offer music and give pleasure to people.
Meanwhile, Jem and Scout find two carved soap figures in the knothole of a tree at the edge of the Radley property. The figures resemble themselves, and later that night, Jem shows Scout a box containing marbles, an old pocket watch, a whistle, a crayon, and other items from a mysterious giver.
As another summer arrives and Tom Robinson’s trial looms closer and closer, racial tensions in Maycomb begin to escalate. Atticus is hatefully ridiculed by the town, especially by Mr. Ewell, who calls him a “n—er lover.” One night, Atticus decides to stand guard outside the jail where Tom is being held. A lynch mob, comprising of Maycomb’s most racist and ignorant men, surrounds the jail and demands that Atticus to move. Sensing the tense and dangerous situation, Scout, Dill, and Jem run over to the mob. Atticus urges them to go home, but Scout innocently engages in a candid yet alarming conversation with Walter Cunningham Sr., one of the men in the mob. Her words embarrass the crowd—who soon dissipates—and thereby prevent a potential lynching.
The next day, the vast majority of Maycomb’s population visit the courthouse to watch the explosive, dramatic trial. Atticus prohibits the children from attending the trial, but they go anyway. The elderly Baptist minister Rev. Sykes allows the children to join the black audience on the balcony of the courtroom, as the rest of the courthouse is packed with spectators.
The courtroom sequence comprises four examinations or cross-examinations: Sheriff Tate, Mr. Ewell, Mayella, and Tom. Tate reveals that nobody called a doctor on the night of Mayella’s beating and rape, and that Mayella was severely beaten. Then, Mr. Ewell testifies that when he came home that night, he found Tom on top of Mayella. Atticus then hands paper and pencil to Ewell and requests him to write his name. Ewell struggles, but reveals himself to be left-handed. Atticus argues that Tom has a crippled left arm, which disqualifies him as the supposed rapist, who would have had to extensively use his left hand to assault Mayella before raping her. Atticus implies that because Ewell is left-handed, he—not Tom—was the one who beat up Mayella. Outraged, Ewell complains to the judge: “That Atticus Finch is tryin' to take advantage of me. You gotta watch lawyers like Atticus Finch."
Mayella’s testimony comes next. During cross-examination, her statements about her relationships with Tom and her father are confusing and contradictory; she is obviously lying. Atticus challenges her testimony, asking, "Do you want to tell us what really happened?" Mayella then loses her remaining composure, shouts at Tom and the jury, and runs from the witness stand.
Tom’s testimony contradicts Mayella’s false story. He claims she often invited him inside the fence to do chores for free for over a year, and on the night of the attack, Mayella attempted to seduce him. When the circuit solicitor, Mr. Gilmer, asks Tom why he felt compelled to do chores for Mayella, Tom somewhat unwisely states that he felt sorry for the white woman.
Later, Atticus delivers a passionate, final defense summation of Tom to the all-white jury. He states the case should never have been brought to trial because of the lack of evidence, points out the blatant contradictions of Mayella’s testimony, and claims she lied due to the overwhelming guilt concerning her sexual attraction to a black man, a horrific offense at the time. He powerfully implies that Mayella failed to seduce Tom Robinson and falsely accused him of rape after her father attacked her for making advances toward a black man.
After hours of deliberation, though, the jury pronounces Tom guilty. Atticus urges Tom not to be too disappointed; the case was doomed from the start because of the prejudiced white jury, and they would ask for an appeal. As the courtroom clears, Atticus gathers his belongings and the black spectators stand up to show their respect and admiration for his passionate defense. Rev. Sykes says, “Miss Jean Louise, stand up. Your father’s passin’” to Scout, who then rises.
That night, Tate informs Atticus that Tom supposedly tried to escape jail and was shot to death by the authorities. Atticus, accompanied by Scout and Jem, then goes to the Robinson household to deliver the news. Mr. Ewell confronts Atticus in the Robinson yard and spits into his face; Atticus glares at him and climbs back into his car.
Mr. Ewell gets revenge on Atticus the following fall. Jem and Scout walk home from the Halloween pageant at their school, and Ewell follows the children home and suddenly attempts to kill them with a large kitchen knife. He breaks Jem's arm, and Scout becomes helpless throughout the attack due to a visually and physically confining ham costume. Fortunately, Boo Radley saves Jem and Scout's lives and stabs Ewell.
Scout finally meets the shy, ghostly Boo—whose stark paleness suggests a life spent in a sun-deprived setting—at home. Scout no longer fears Boo and they sit quietly together on the swing while Tate and Atticus discuss the night’s events. In an attempt to avoid the innocent, reclusive Boo from being tried for murder and receiving unwanted public attention from Maycomb residents, Tate fabricates a story, asserting that a drunk Ewell fell and killed himself on his knife. Atticus hesitantly agrees to cover up the truth. With a newfound maturity, Scout walks Boo home and imagines how he views the world. The film concludes with the adult version of Scout admitting how she often reflects on these memories of her childhood, noting that Atticus stayed in the injured Jem’s room all night and was there when he woke in the morning.
