Native Son is a novel that follows the life of Bigger Thomas, an impoverished young black man living in Chicago in the 1930s. Bigger tries to get a job to help his family, but everything backfires when he accidentally kills the daughter of his employer. He burns her body in the family furnace, and later also kills his girlfriend Bessie. He is caught, and while imprisoned receives regular visits from Max, a lawyer. Together they discuss Bigger's life and his relationship to the world as a black man.
Bigger Thomas wakes up in a dark, small room at the sound of the alarm clock. He lives in one room with his brother Buddy, his sister Vera, and their mother. Suddenly, a rat appears. The room turns into a maelstrom and after a violent chase, Bigger claims the life of the animal with an iron skillet and terrorizes Vera with the dead rodent. Vera faints and Mrs. Thomas scolds Bigger, who hates his family because they suffer and he cannot do anything about it.
That evening, Bigger has to see Mr. Dalton for a new job. Bigger's family depends on him. He would like to leave his responsibilities forever but when he thinks of what to do, he only sees a blank wall. He walks to the poolroom and meets his friend, Gus. Bigger tells him that every time he thinks about whites, he feels something terrible will happen to him. They meet other friends, G.H. and Jack, and plan a robbery of the white wealth. They are all afraid of attacking and stealing from a white man, but none of them wants to admit their concerns. Before the robbery, Bigger and Jack go to the movies. They are attracted to the world of wealthy whites in the newsreel and feel strangely moved by the tom-toms and the primitive black people in the film, but they also feel that they are equal to those worlds. After the cinema, Bigger returns to the poolroom and attacks Gus violently, forcing him to lick his blade in a demeaning way to hide his own cowardice. The fight ends any chance of the robbery occurring; Bigger is obscurely conscious that he has done this intentionally.
When he finally gets the job, Bigger does not know how to behave in the large and luxurious house. Mr. Dalton and his blind wife use strange words. They try to be kind to Bigger, but they actually make him very uncomfortable; Bigger does not know what they expect of him. Then their daughter, Mary, enters the room, asks Bigger why he does not belong to a union, and calls her father a "capitalist". Bigger does not know that word and is even more confused and afraid to lose the job. After the conversation, Peggy, an Irish cook, takes Bigger to his room and tells him that the Daltons are a nice family, but that he must avoid Mary's communist friends. Bigger has never had a room for himself before.
That night, he drives Mary around and meets her Communist boyfriend Jan. Throughout the evening, Jan and Mary talk to Bigger, oblige him to take them to the diner where his friends are, invite him to sit at their table, and tell him to call them by their first names. Bigger does not know how to respond to their requests and becomes very frustrated, as he is simply their chauffeur for the night. At the diner, they buy a bottle of rum. Bigger drives throughout Washington Park, and Jan and Mary drink the rum and have sex in the back seat. Jan and Mary part, but Mary is so drunk that Bigger has to carry her to her bedroom when they arrive home. He is terrified someone will see him with her in his arms; however, he cannot resist the temptation of the forbidden, and he kisses her.
Just then, the bedroom door opens, and Mrs. Dalton enters. Bigger knows she is blind but is terrified she will sense him there. He silences Mary by pressing a pillow into her face. Mary claws at Bigger's hands while Mrs. Dalton is in the room, trying to alert Bigger that she cannot breathe. Mrs. Dalton approaches the bed, smells alcohol in the air, scolds her daughter, and leaves. As Bigger removes the pillow, he realizes that Mary has suffocated. Bigger starts thinking frantically, and decides he will tell everyone that Jan, her Communist boyfriend, took Mary into the house that night. Thinking it will be better if Mary disappears and everyone thinks she has left Chicago, he decides in desperation to burn her body in the house's furnace. Her body would not originally fit through the furnace opening, but after decapitating her, Bigger finally manages to put the corpse inside. He adds extra coal to the furnace, leaves the corpse to burn, and goes home.
Bigger's current girlfriend Bessie suspects him of having done something to Mary. Bigger goes back to work. Mr. Dalton has called a private detective, Mr. Britten. Britten interrogates Bigger accusingly, but Mr. Dalton vouches for Bigger. Bigger relates the events of the previous evening in a way calculated to throw suspicion on Jan, knowing Mr. Dalton dislikes Jan because he is a Communist. When Britten finds Jan, he puts the boy and Bigger in the same room and confronts them with their conflicting stories. Jan is surprised by Bigger's story but offers him help.
Bigger storms away from the Daltons. He decides to write a false kidnapping note when he discovers that the owner of the rat-infested flat his family rents is Mr. Dalton. Bigger slips the note under the Daltons' front door and then returns to his room. When the Daltons receive the note, they contact the police, who take over the investigation from Britten, and journalists soon arrive at the house. Bigger is afraid, but he does not want to leave. In the afternoon, he is ordered to take the ashes out of the furnace and make a new fire. He is terrified and starts poking the ashes with the shovel until the whole room is full of smoke. Furious, one of the journalists takes the shovel and pushes Bigger aside. He immediately finds the remains of Mary's bones and an earring in the furnace, and Bigger flees.
Bigger goes directly to Bessie and tells her the whole story. Bessie realizes that white people will think he raped the girl before killing her. They leave together, but Bigger has to drag Bessie around because she is paralyzed by fear. When they lie down together in an abandoned building, Bigger rapes Bessie and falls asleep. In the morning, he decides that he has to kill her in her sleep. He hits Bessie on the head with a brick before throwing her through a window and into an air shaft. He quickly realizes that the only money he had was in her pocket.
Bigger runs through the city. He sees newspaper headlines concerning the crime and overhears different conversations about it. Whites hate him and blacks hate him because he brought shame on the black race. After a wild chase over the rooftops of the city, the police catch him.
During his first few days in prison, Bigger does not eat, drink, or talk to anyone. Then Jan comes to visit him. He says Bigger has taught him a lot about black-white relationships and offers him the help of a communist lawyer named Max. In the long hours Max and Bigger spend talking, he starts understanding his relationships with his family and with the world. He acknowledges his fury, his need for a future, and his wish for a meaningful life. He reconsiders his attitudes about white people, whether they are aggressive like Britten, or accepting like Jan. Bigger is found guilty in front of the court and sentenced to death for murder; however, at the end of the novel, he appears to come to terms with his fate.