Four Black South African gang members—Tsotsi, Boston, Butcher, and Die Aap—are sitting in Tsotsi’s room, waiting for night, when Tsotsi suggests they kill a man on the train. Sadistic Butcher and stupid Die Aap agree. Intellectual, cowardly Boston resists for a moment but eventually submits. The men murder a worker, Gumboot Dhlamini, who left his wife behind to work in the city and had almost earned enough to return to her.
After the murder, Boston vomits. The gang goes to a shebeen where they and a drunk woman are the only customers. Tsotsi thinks how he hates Boston, because Boston asks questions about his past that Tsotsi doesn’t know the answers to—Tsotsi has no memories of childhood. Butcher and Die Aap take the drunk woman outside and rape her. Alone with Tsotsi, Boston asks him whether he feels sympathy for the gang’s victims, asks about Tsotsi’s past, and, finally, whispers that Tsotsi must have a soul. Tsotsi attacks him. Butcher and Die Aap reenter the shebeen and pull Tsotsi off Boston. Tsotsi leaves.
Boston’s words echo in Tsotsi’s mind. To distract himself, he runs until he’s exhausted and stops under some bluegum trees to rest. He spies a young Black woman carrying a shoebox approaching the bluegums. As she passes, he pins her against a tree and shoves a knee between her legs, but a noise from the shoebox shocks him into stepping back. The woman shoves the shoebox at Tsotsi and runs. Inside the shoebox is a baby.
The next day, Saturday, Tsotsi goes to buy milk for the baby. Terrified of Tsotsi, the store owner Cassim tricks him into buying condensed milk to get him to go away. Tsotsi goes back to his room and feeds the baby. Worried Butcher or Die Aap will catch him taking care of a baby, Tsotsi hides the baby in the ruins near the white neighborhood. There, Tsotsi remembers that the night before, the baby triggered a memory of a yellow dog. He realizes he’s hoping the baby will trigger more memories.
When Tsotsi returns to his room, Butcher and Die Aap are waiting for him in the street. Butcher and Die Aap bother Tsotsi about the gang’s plan for the night until he tells them they’ll go to the city. In the city, Tsotsi identifies a target, a beggar named Morris Tshabalala who lost his legs in a mining accident and moves around on his hands. While stalking Morris, however, Tsotsi realizes he feels sympathy for his victim. Instead of killing Morris, he has a long conversation with him. When Morris asks Tsotsi why Tsotsi has to kill him, Tsotsi realizes he doesn’t have to and spares Morris’s life.
On Sunday morning, Tsotsi goes to check on the baby in the ruins. Ants have swarmed the opened condensed milk tin and the baby’s shoebox. Tsotsi kills the ants on the baby’s face, bundles the baby up, and leaves.
Down the street from Tsotsi’s room, people are filling buckets at a communal water tap. Among them is a young mother, Miriam Ngidi, and her baby. After Miriam returns to her room, she hears a knock on the door. When she opens it, Tsotsi forces his way inside and threatens to kill her baby if she doesn’t cooperate with him. He brings her to his room and demands she breastfeed the baby he has adopted. After Miriam cleans and breastfeeds the baby, she asks where his mother is. When Tsotsi doesn’t answer, Miriam says that “a bitch in a backyard would look after its puppies better” and leaves.
This incident triggers a flashback in Tsotsi. In the flashback, Tsotsi is a 10-year-old named David, living with his mother and a yellow dog pregnant with puppies. His mother tells him that after a long absence, his father will be returning the next day. That night, David wakes up to policemen raiding the neighborhood. They break down his family’s door. One policeman demands his mother’s pass and calls her a slur. Before she can answer, the police drag her outside and put her in a van. When the vans are full, the police drive away. The next morning, David falls asleep and wakes to someone pounding on the door and yelling the name “Tondi.” David runs and hides in the back yard. He hears the intruder come into the yard. The yellow dog snarls at the intruder, and the intruder kicks her. After a neighbor tells the intruder the police took Tondi, the intruder leaves. David sees the intruder has broken the yellow dog’s back legs. She crawls toward David, gives birth to dead puppies, and dies.
David runs away from home. He is wandering the streets when a gang of orphans finds him and invites him to join them. One orphan, Petah, asks David’s name. David tells him but says that David is “dead” now. Later, while scavenging for food with the orphan gang, David hears a shopkeeper call him a “tsotsi.” He chooses Tsotsi as his new name.
On Monday, Tsotsi wakes to Die Aap knocking on his door. Tsotsi hides the baby and asks Die Aap what he wants. Die Aap tells Tsotsi that Butcher is angry with Tsotsi and has joined a different gang. Die Aap suggests he and Tsotsi form a new gang. Tsotsi refuses and tells Die Aap to leave.
Tsotsi finds Miriam and brings her back to his room. When Miriam asks the baby’s name, Tsotsi tells her it’s David. When Miriam asks whether Tsotsi is the child’s father, he tells her David didn’t know his father. Miriam tells Tsotsi the baby is sick and asks to adopt and care for him. Tsotsi refuses, saying the baby belongs to him.
Tsotsi hides the baby in the ruins and goes looking for Boston. Tsotsi finds Boston unconscious in a shebeen. He carries Boston back to his room and goes to buy food. When Boston wakes up in Tsotsi’s bed, Tsotsi explains to Boston about caring for the baby and sparing Morris’s life. He demands that Boston tell him what is happening to him. Boston tells Tsotsi that he’s changing. When Tsotsi asks what has changed him, Boston tells Tsotsi he’s now asking about God. Boston sleeps in Tsotsi’s bed that night, and the next morning, even though Tsotsi wants him to stay, he leaves.
The next day, Tsotsi is sitting on a sidewalk outside a church when the church gardener, Isaiah, offers him some tea. Tsotsi asks Isaiah about the church and about God. Isaiah explains as best he can. He then invites Tsotsi to come to church that evening. Later, Tsotsi carries baby David to Miriam’s and tells her the baby vomited up the milk she left. Miriam gets medicine for the baby. She restates her desire to care for the baby. Tsotsi begs her not to take the baby from him. He leaves the baby with her when he hears church bells ringing—presumably to attend the service Isaiah invited him to—but comes back, takes the baby, and hides it again overnight.
The next morning, Tsotsi wakes up thinking he needs to tell Miriam his real name, David Madondo. He is walking through town when he hears bulldozers. White people have been complaining about Black people moving back into the ruins, so bulldozers have come to raze the ruins again. Tsotsi runs to save the baby, but a bulldozer knocks a wall on top of Tsotsi and kills him. When his body is dragged from the wreckage, there is a “beautiful” smile on his face.
