Bigger Thomas, a 21-year-old black man, wakes up in the one-room apartment he shares with his younger siblings and their mother. Bigger and his brother must catch the rat that is scurrying around the room. When the rat bites him, Bigger loses his temper. He kills it with a skillet and then crushes its head. His mother orders him to throw it out, but Bigger can’t resist dangling the bloody carcass in front of his sister until she faints.
Bigger’s mother reminds him of the job interview he has scheduled for that afternoon. In 1930s Chicago, the opportunity to be a rich white man’s driver is rare. Bigger resents her pressuring him and does not want the job.
Feeling trapped, Bigger leaves to find his friends. They have made tentative plans to rob a white man’s store later that day. Until now, they have only robbed properties owned by black proprietors, as they know the police do not investigate those crimes. Bigger argues with his friend Gus, who is having second thoughts about the robbery. Bigger will not admit he is frightened, and Gus’ fear only stokes his anger. Eventually, Gus agrees to help with the crime.
Bigger goes to the movie with another friend, as they wait to commit the robbery. While watching a newsreel, the two men masturbate. One of the stories is about a young woman, Mary Dalton. She is the only child of millionaire Henry Dalton, with whom Bigger is to interview with for a job.
Mary has scandalized her family by taking up romantically with a known communist. Bigger, who had been dreading the job, now daydreams what it would be like to work for such people. He regrets agreeing to the robbery, as it might prevent him from getting the job with the Dalton family. In the end, he sabotages the robbery plans by attacking Gus for being late to meet up with the rest of the gang.
Bigger arrives at the Dalton mansion for his interview and is intimidated by its size and beautiful furnishings. Bigger is agitated with himself because he can’t seem to say anything but “Yessuh” and “Nawsuh” to Mr. Dalton. Mary Dalton enters the room. Seeing Bigger, she asks if he is part of the union. Bigger knows only that unions are supposed to be bad, and he finds himself angry with Mary for making him even more nervous. Eventually, Mary leaves, and Mr. Dalton offers Bigger the job. His first outing will be to take Mary to a class at the university that evening.
Peggy, the Daltons’ maid, shows Bigger the room where he will be staying. It is larger than the apartment he and his family share. After serving him dinner, Peggy shows Bigger the furnace he must also tend to as part of his duties. She shares how nice the Dalton family is to their employees.
Their former driver, also black, was encouraged to go to night school and further his education. He then got a better job with the government. Mrs. Dalton, the blind matriarch of the family, also encourages Bigger to go back to school. The Daltons unnerve Bigger. He feels they must have ulterior motives, as white people never try to help blacks.
That evening, Bigger picks up Mary to take her to her class, but once in the car she informs him she is going elsewhere and asks him to keep it a secret. Bigger agrees, as she is white and he must do as she asks. He drives her to meet her boyfriend, Jan, the communist from the newsreel Bigger watched earlier.
Jan insists on shaking hands with Bigger and driving the car. Bigger’s anger sparks again when Mary climbs into the front seat with them. Although Mary and Jan are being friendly, Bigger is thrown into a state of near panic. The white world has been off-limits to him, and he doesn’t know how to act. He believes Mary and Jan are making fun of him when they insist he eat with them at a black restaurant.
Bigger finally agrees to be their guest, but it is only when Jan encourages him to have several rum drinks that Bigger relaxes. Jan tells Bigger how the communists want to help black people gain equality in America. Mary insists they want to be his friends. After dinner, Bigger drives them around the park while the two make out in the back seat. He then drops off Jan and takes Mary home.
Mary is too intoxicated to walk without Bigger’s help. Terrified, as he knows it violates every social taboo, he brings her up to her bedroom. As she swoons against him, he gives in to temptation and kisses her. He lays her down and gropes her breasts but is stunned when Mrs. Dalton enters the room. Knowing she is blind, Bigger thinks that if he can keep Mary quiet, her mother will leave without discovering him. In his panic, he accidently smothers Mary. Mrs. Dalton kneels by the side of the bed and smells alcohol. She prays for Mary, and then leaves the room.
Bigger frantically tries to cover his crime. He puts Mary’s body into the trunk she had asked him to take to the train station in the morning as she was supposed to go to Detroit. As he passes the furnace, he decides to decapitate her and burn the body. He plans on telling the family that Mary left on her trip as expected. He will also say that Jan accompanied Mary up to her room, so that if anything is amiss they will suspect the communist. Bigger takes money from Mary’s purse and goes to his family’s apartment, hoping to use them as an alibi.
In the morning, Bigger returns to the Daltons’ home with a sense of invincibility. He has killed a white woman, and no one knows. He has money in his pocket to escape. For the first time in his life, he feels alive. He enjoys watching the Daltons and Peggy wonder about Mary’s whereabouts until Mrs. Dalton remarks that her daughter would not have gone away without all her new clothes. Bigger realizes he forgot to pack her trunk.
After being questioned by the family, Bigger goes to visit his girlfriend, Bessie. He shows her the money, and after she questions him, he tells her that Mary ran away, and he took the cash from her room. He comes up with a plan to get more money by writing a ransom note and making it look like communists kidnapped Mary. Bessie reluctantly agrees to help him.
Bigger returns to the Dalton house and is questioned by Mr. Dalton and a private investigator named Britten. Bigger plays the part of an ignorant, subservient black man and repeats the story that Mary and Jan went up to her room. Britten suspects Jan and Bigger are partners, but Mr. Dalton tells him to leave Bigger alone. They bring in Jan for questioning, and he denies everything but is surprised Bigger is implicating him. Jan confronts Bigger on the street. Bigger pulls out a gun and chases Jan away.
Bigger visits Bessie and admits he killed Mary. She begs him to leave her out of the ransom plans, but he cannot risk her telling anything to the police. He writes a ransom note and slips it under the Daltons’ front door. The press arrives and is kept in the basement with the furnace. When Bigger is ordered to sweep out the ashes, one of reporters spots pieces of bone and an earring. As they swarm to investigate, Bigger slips out of the house and flees to Bessie. He forces her to hide in an abandoned building with him. When she falls asleep, he beats her head with a brick. He throws her body down an airshaft. Too late, he realizes she had all Mary’s money in her coat pocket. The police and vigilantes search for Bigger throughout the night. Innocent black people are terrorized during the hunt. Bigger is finally caught the following night.
Bigger is visited in jail by his family, friends and the Daltons. Bigger’s mother begs the Daltons for mercy, but their hands are tied. The court will decide his fate. Mr. Dalton promises to speak to the Thomas’ landlord, to keep them being evicted from their apartment. Jan also visits, and for the first time, Bigger sees a white man as an individual, not an entity that seeks to keep him confined. Jan introduces him to Mr. Max, a lawyer who wants to defend him. After everyone leaves, the state’s attorney talks to Bigger. Bigger confesses to killing Mary and Bessie.
Bigger is indicted for his crimes and pleads guilty. Mr. Max argues for the opportunity to relate the extenuating circumstances of Bigger’s life in order that the judge might give him life in prison, rather than the death penalty. Max argues passionately about the poverty and degradation Bigger has endured at the hands of white Americans. The court’s rush to judgment is a symbol of its own guilt. White people know they have victimized and abused blacks since shackling them in slavery. Even now, when they are supposed to be free, black people are segregated and kept in poverty. Killing Bigger will not help the problem but only fuel the anger within the black community. In prison, at least, Bigger would be given a number, an identity, for the first time in his life. Although Bigger does not understand everything Max says, he is proud that a white man fought hard for his life.
The state’s attorney argues that Bigger is nothing more than an animal, filled with lust. He charges Bigger raped Mary and killed her to cover up his crime. The judge sentences Bigger to death. Max visits him in jail after he fails to obtain a pardon from the governor. Bigger has spent many hours contemplating his life. He believes that his killing must have been a good thing, because for the first time he felt alive. Max is horrified, but Bigger argues it makes sense to him. He asks Max to tell his mother not to worry and then asks him to tell Jan hello. In his last moments, he is able to break social taboo and call a white man by his first name.