While walking home from the movie theater, Ponyboy Curtis, a member of the gang called “Greasers” (in reference to their style of wearing their hair long and greasy), is confronted and threatened by members of a rival gang, the Socials or “Socs.” Members of Ponyboy’s gang come to his rescue, among them his older brothers Darry and Sodapop, all three of whom were orphaned when their parents were killed in an auto accident. The following evening, Ponyboy and his friend and fellow member Johnny – an unusually sensitive boy whose last experience with the Socs has caused him to carry a switchblade for protection – are at the movies with Dally, the most hardened and violent of the Greasers, who proceeds to attempt to flirt with two Soc girls sitting in front of them. After telling Dally to lay off, Ponyboy and Johnny strike up a conversation with the girls, whose names turn out to be Cherry and Marcia. Two-Bit, another Greaser, shows up at the theater, and the boys offer to walk the girls to his house so that he can give them a ride home. However, their walk is cut short when they encounter Randy and Bob, the girls’ boyfriends, who have obviously been drinking. The rival gangs face off, but Cherry and Marcia immediately ask the Socs to take them home in order to prevent a fight.
When Ponyboy arrives home, his brother Darry – ostensibly the boys’ father since their parents died – is furious that he has arrived so late. An argument between the two quickly escalates into yelling, and without thinking Darry slaps Ponyboy across the face, causing Pony to run away. He immediately runs into Johnny, and the two head for the local park. There they are cornered by a large group of drunk Socs, one of whom, Bob, holds Ponyboy’s head underneath the water of a fountain until Johnny is forced to use his switchblade on the attacker, killing him. Frightened for their lives, Ponyboy and Johnny run to Dally, who has had experience running from the law. He gives them some money and a gun and tells them to hide out in an abandoned church outside town.
Cutting and (in Ponyboy’s case) bleaching their hair to disguise themselves, Ponyboy and Johnny remain at the church, reading poetry and Gone with the Wind to pass the time. Dally comes to visit and buys the boys lunch, telling them that relations between the Greasers and the Socs have deteriorated since Bob’s killing and that a huge rumble is scheduled for the following night. Above Dally’s protestations, Johnny decides to turn himself in, but on the way home the boys notice that the abandoned church has caught fire and there are several children trapped inside. In a moment of bravado, Johnny and Ponyboy break their way inside to save them, Dally cursing close behind. The children are rescued, but Ponyboy and Dally suffer burns and Johnny is critically injured when a roof beam falls, breaking his back.
The three are rushed to the hospital, where they are met with open arms by Darry and Sodapop. The papers the next morning declare that Johnny and Ponyboy are heroes, but also that they will have to face the juvenile courts for Bob’s death. Ponyboy and Two-Bit go for a soda, and run into the Soc Randy, who says he is sick of fighting and is not going to the rumble that night. They visit Dally and Johnny, but are disturbed by the seriousness of Johnny’s condition. Ponyboy encounters Cherry on the way home, and berates her for not visiting Johnny, but forgives her. With the help of Dally, who has escaped from the hospital, the Greasers win the rumble that evening, and Dally and Ponyboy visit Johnny to tell him the good news. Unfortunately Johnny is fading fast, and passes away as they watch. Dally is thrown into a violent frenzy at this, and Ponyboy runs home to warn the others. Dally calls to tell them that he has robbed a liquor store, but by the time the others reach him he is being gunned down after raising his gun to the police. Ponyboy is overwhelmed and loses consciousness.
When he awakens, he finds that the rumble has left him with a concussion and several days have passed. Soon afterward, he attends his hearing at the juvenile court, where the judge releases him from guilt and allows him to stay with his brothers. Ponyboy feels hopeless and empty, and his hostility finally forces Sodapop to confront him, making him promise not to argue with Darry anymore. As he says, "nothing gold can stay." In an attempt to deal with Dally and Johnny’s deaths, Ponyboy begins to write a story for English class, which it is soon revealed is the novel itself.