According to the publisher, Jean Louise "is forced to grapple with issues both personal and political as she tries to understand her father's attitude toward society and her own feelings about the place where she was born and spent her childhood." Go Set a Watchman shows early versions of many of the characters that would later appear in To Kill a Mockingbird.
The novel follows a woman in her twenties, Jean Louise "Scout" Finch who travels from New York to the fictional town of Maycomb, Alabama, to visit her family. The early sections of the book deal with her return and various incidents around the town as she reconnects with her aunt Alexandra, her uncle Jack, a retired doctor, and her father Atticus, a lawyer and former state legislator. Aside from visiting her family, the central reconnection is with a childhood friend and suitor, Henry "Hank" Clinton, who lived across the street and now works with her father. The Supreme Court Brown vs. Board of Education decision and the NAACP are introduced as being controversial in the community.
Returning from a trip to her ancestral home, Jean Louise and Henry are passed by a car of Negroes travelling dangerously at high speed. Jean Louise is startled and Henry mentions that the Negroes in the County now have money for cars but neglect to get licenses and insurance. The next day is spent dealing with the minor scandal the swim the previous evening has caused and there is flashbacks to Jean Louise's youth, spent with another neighbor friend, Charles Baker "Dill" Harris and her older brother Jeremy "Jem" Finch, who has since died of a heart condition which also killed her mother.
Late in the day, after finding a pamphlet titled "The Black Plague" among her fathers papers, Jean Louise follows him to a Citizens’ Council meeting. At the meeting, Atticus rises and briefly introduces a Mr. Grady O'Hanlon. O'Hanlon stands and delivers an aggressively racist speech. Jean Louise watches in secret from the empty balcony, and is horrified. There is a flashback to her youth where her father successfully wins a case defending a one armed Negro against a rape allegation. She can't forgive that he has now betrayed her and she flees the hall. She goes to the site of her former childhood home, which is now an ice cream parlor. She orders an ice cream but can't keep it down and eventually goes home and goes to sleep devastated and exhausted.
After having a dream about her old family Negro maid Calpurnia, who Jean Louise sees as a mother figure, Jean Louise goes downstairs and has breakfast with her father. There is a phone conversation and it is revealed that Calpurnias grandson has killed a drunk pedestrian the previous night speeding through town in his car. Atticus agrees to take the case in order to stop the NAACP getting involved.
Jean Louise drives out of town, past the site of the accident and visits Calpurnia. The African American characters are depicted as being only marginally civilized and she is given a frosty welcome. Calpurnia treats her politely but coldly and Jean Louise leaves devastated.
She returns to her fathers house and helps her aunt host a womans meeting. Her aunt and her friends make prejudiced comments about Negroes, Communists and Catholics. Jean Louise herself is revealed to have negative opinions of young married mothers in general.
At lunch with her Uncle Jack, Jean Louise questions why Atticus was at the meeting and why is everybody acting so crazy. Jack laughs and says she should stop being so immature and know her father better than that. He said that of course Atticus hasn't suddenly become racist, but that what he is doing by being a member of the council is trying to slow down federal government intervention into state politics. Her uncle then proceeds to give her a lecture on the complexity of history, race and politics in the South, purposefully and ambiguously trying to get Jean Louise to come to a conclusion, which she struggles to grasp. When she fails to see his point, he dismisses her and after she leaves, is seen making a phone call.
Jean Louise is next seen sitting behind the ice cream shop. She has a flashback to when she was a teenager and went to her first dance. During the flashback she recalls that there was an incident where Atticus planted the seed for an idea in Henrys brain and then let him come to the right conclusion on his own.
Jean Louise goes to the law office with the intention of seeing her father. She finds Henry instead and they go out to have coffee. After a brief conversation about marriage being a surrender of your identity, she tells him she doesn't love him and will never marry him. She screams at him about her disgust at seeing him and her father at the council meeting the previous day. Henry explains that sometimes people have to do things they don't want to do. He tells her about the realities of being a member of a community, that certain things are expected. That she is naive to the social realities of class, because she grew up in a prominent family. He says that he could go and scream his ideals from the rooftops but because of his lack of social capital it wouldn't get him anywhere, in fact, it would only have the reverse effect. She again screams at him that she could never live with a hypocrite; only to notice that Atticus is standing behind them smiling.
Henry leaves and Jean Louise goes into the office with her father. They have a lengthy discussion on the topics of Segregation and Integration, the NAACP, State Rights and the Constitution, the negative aspects of Bureaucracy and Libertarianism. Atticus provocatively argues that the Negroes of the South are not ready for full civil rights and the Supreme Courts decision was not only unconstitutional but irresponsible. That it will actually have the reverse effect of slowing down successful Integration rather than speeding it up. He says that he considers himself a sort of "Jeffersonian Democrat" and that the Negroes now have their liberty, but that the right to vote is something that has to be earned, not something that should just be given. That Jefferson believed being a man didn't give a man the right to vote, he needed to prove himself a responsible man. Jean Louise gets very emotional and says she doesn't understand why he is deliberately queering and twisting his pitch. She says that although she agrees that the South is not ready to be fully Integrated she says that the court was pushed into a corner by the NAACP and had to act. She says that now that it has that they have to try and work with the decision instead of opposing it as it is only making it worse. She is devastated by his positions as they are contrary to everything he has ever taught her. Atticus is silent during her heated and aggressive argument and says he killed her because he had to. She begins to curse her at which point he calmly and almost amusingly says that he loves her and then dismisses her.
She returns to the family home furious and as she starts to pack to leave her aunt enters and questions what she's doing. Jean Louise starts berating her about the family and the community and is surprised to see her aunt in tears. Jean Louise apologizes and takes her suitcase out to the car at which point a taxi arrives carrying her Uncle. He asks where she is going and she tells him angrily that she is going to the train station. She begins to rant at him to leave her alone and slams the trunk down before he backhands her across the mouth staggering her and telling her that he is trying to attract her attention.
He then takes her into the lounge and tells Alexandra to bring her some whiskey, which she drinks quickly. He says he's never struck a woman before in his life and might have a whiskey himself. Her uncle tells her that she is now ready for him to talk straight to her. He tells her to think of all the things that have happened over the past two days and how she has processed them. When she says she can now stand them he tells her it is bearable because she is her own person now. He tells her that at one point she had fastened her conscience to her fathers, assuming that her answers would always be his answers. He makes her question how Atticus was acting during their discussion. She says that Atticus deliberately didn't try to defend himself so that his daughter could finally bring herself to disagree with him. Her uncle tells her that Atticus was letting her break her idols, so that she could reduce him to the status of a human being. He tells her that she is very much like her father except that she is a bigot, where as her father isn't. Jean Louise goes to the bookshelf and looks up "Bigot". She asks her uncle to explain himself.
He explains that when bigots opinions are challenged, they don't try to listen, they lash out. She thinks about why Atticus let Mr. Hanlon speak his racist rant. She feels bad about what she said to Atticus but tries to defend herself by saying the Klan uses violence. He interrupts her and says and that you didn't consider when you called your father Hitler, that the Klan can parade around all it wants but when it starts beating people, don't you know who the first person would be that would try and stop it? He tells her that her father lives by the law, he'll do his best to try and stop someone beating somebody else and then he'll turn around and try to stop no less than the federal government. He tells Jean Louise that she judges people by their individual merits and have never been prodded to look at people as a race. She says that may be so, but it's not like she wants to run out and marry a Negro or something. He says that there is nothing that says just because you go to school with Negroes that you'll automatically want to marry one. He then tells her to take him home and go pick up her father. On the way to the car he asks her if she has ever really considered coming home. She says no, and he tells her she should consider it. He says that it is an aspect of the South that she has missed, that she might be surprised with how many people down there are on her side. She asks him what she should do about Henry, He tells her to let him down easy. He tells her that she and Jem were very special to him as he was in love with their mother and that he thought of Jem and Scout as his dream children. She asks if Atticus knew, to which he replies "Certainly".
She returns to the office and makes a date with Henry for the evening. She reflects that Maycomb has taught him things she had never known and that Maycomb had rendered her useless to him except as his oldest friend. Atticus calls from his office, asking if that is her and she is startled by his voice and says yes. She goes to apologize to him but he interrupts her and tells her how proud of her he is. She says she doesn't understand men at all and never will. He says he hoped that a daughter of his would stand her ground for what she thinks is right. She reflects that she didn't want her world disturbed but that she tried to crush the man who is trying to preserve it for her. That she can't beat him but that she can't join him either. She tells him that she thinks she loves him very much. As she follows him to the car and watches him get into the front seat she silently welcomes him to the human race, seeing him as just a man for the first time, which makes her tremble. She slips behind the steering wheel, careful not to bump her head.