In Tulsa, Oklahoma, in the late 1960s, 16-year-old Bryon Douglas lives with his mother and his foster brother and best friend, Mark Jennings. Mark’s parents killed each other in a drunken fight when he was younger, and he’s lived with Bryon and Bryon’s mother ever since. The boys are extremely close and enjoy breaking rules together: Mark is a notorious thief who is on probation for hotwiring cars, while Bryon is a perpetual liar who hustles people at pool.
One night, Bryon and Mark sneak into Charlie’s bar despite being underage. They plan to make some money playing pool, but there is no one to hustle. Charlie, the bartender and owner, warns them that they could get in trouble for hustling. He also says that they have run up a $3 tab, and that if they don’t pay by the next day, he’s going to beat them up.
After Bryon and Mark leave, they run into their 13-year-old friend M&M. Bryon describes M&M as serious, intelligent, very trusting, and a little strange. But when they part ways, Bryon and Mark observe three guys—including their classmate, Curly Shepard—trailing M&M. Their classmates start to mug M&M, but Mark and Bryon attack the three boys, warding them off. Mark is also able to pickpocket the $3 they owe Charlie from the attackers.
The next day, Bryon and Mark visit Bryon’s mother in the hospital where she’s recovering following an operation. She asks the boys to go visit a kid across the hall who hasn’t had any visitors. Bryon first goes down to get a burger and meets Cathy, M&M’s older sister who is working in the snack bar. She has just returned home from private school, and Bryon is immediately smitten with her. Bryon then returns upstairs and visits the kid across the hall, whose name is Mike. Mike is badly injured; he explains that he had stopped his gang from harassing a black girl named Connie and that he had then driven her home. But when they arrived at her address, a group of black men surrounded his car, and she told them to kill Mike—which is how he ended up in the hospital. Still, he says, he doesn’t hate Connie and can understand that she was probably sick of white people harassing her.
Soon after, Bryon looks for a job to help pay for his mother’s operation because they have very little money. He asks Charlie to work at the bar, but Charlie refuses because Bryon is underage and lies too much. Bryon then asks if he can borrow Charlie’s car on Saturday, and Charlie agrees. Bryon calls Cathy and asks her to a dance, while Mark plans to go solo with a group of guys. This group includes Ponyboy Curtis, whom Bryon dislikes because his ex-girlfriend Angela Shepard dumped him to try and go out with Curtis—even though Curtis rejected her.
On Saturday, Bryon and Cathy dance the whole night and have a great time. Later in the evening, however, they hear a scream from the parking lot. Bryon finds out that Angela had convinced a kid to attack Curtis for rejecting her, but when Mark stepped in, the kid hit him over the head with a bottle. Mark now has a deep gash in his head, and Bryon stays with him in the ambulance and the hospital while he gets stitches. At home, Mark expresses how glad he is that Bryon was there to calm him down, and that he feels that Bryon is really his brother. Bryon says he feels the same way.
The next day, Mark and Bryon reminisce about their childhood antics, and Mark laments that he feels like things are changing. After a few days, Mark is back at school. One day, Bryon hears that Mark got in trouble for stealing the principal’s car so he could drive to his appointment with his probation officer. Bryon is furious, but when he hears Mark was able to talk his way out of punishment, Bryon says angrily that as long as Mark got away with what he did, it’s fine.
Bryon asks Cathy to go out again; he really likes her. Soon after, he and Mark go hustling to make some money. They make $25 off a pair of tough-looking Texans, but when the boys leave the bar, the two men are waiting for Mark and Bryon in the alley. They pull out a gun, planning to beat the boys up. Charlie intervenes with his own gun to rescue the boys, but he is killed in the resulting crossfire.
In the aftermath of Charlie’s death, the Texans are caught and tried, and the police give Charlie’s car to Bryon and Mark. Bryon is consumed by guilt over what happened, but Mark tells him that sometimes “things happen.” Bryon is frustrated that Mark doesn’t understand why he feels guilty, and Bryon spends more and more time talking to Cathy about his feelings. Bryon also starts to make changes in his life. Since his mom has to stay in bed for a month to recover from her operation, Bryon tries more earnestly to get a job. He gets a haircut, puts on clean clothes, and resolves to change his attitude. Bryon also realizes that he loves Cathy, but he has a hard time telling her so.
One day, Bryon, Cathy, M&M, and Mark go driving along a stretch of Tulsa called “the Ribbon,” where many kids hang out. Bryon realizes as they hang out that Cathy and Mark don’t like each other much. M&M, who feels rejected at home, runs away from the car, saying he’s never going to come back. Cathy is distraught.
M&M doesn’t reappear for a week, and Bryon and Cathy search for him every day along the Ribbon. Meanwhile, Bryon gets a job in a supermarket, and Mark starts bringing in money as well—though Bryon doesn’t know where he’s getting it. A few weeks later, Bryon and Mark hang out together, and they soon meet up with a drunk Angela Shepard. She and Bryon drink a bottle of rum, and she passes out. In revenge for the fight she instigated at the party, Mark cuts off her long hair. The boys then drop her on her front yard and return home. There, Mark reveals that he knows where M&M is, and Bryon is furious, saying that Cathy has been worried sick all this time.
The next day, Bryon and Mark go to search for M&M at a hippie house, but the people in the house say that M&M isn’t there. Bryon notes that Mark is very familiar with the house and the people in it. Later that evening, Bryon continues to search for M&M along the Ribbon with Cathy—he decides not to tell her about the hippie house so as not to worry her. After he drops her off, he returns to Terry Jones’s house to pick Mark up. While he waits on Terry’s steps, Tim and Curly Shepard approach him and beat him up in retaliation for cutting off Angela’s hair. As they beat him, Bryon passes out.
When Bryon wakes, Mark is wiping Bryon’s face with a washcloth inside Terry’s house. He stays with Bryon all night, and the next day Mark takes him to the hospital. Bryon receives 15 stitches in his face and gets his ribs taped. Bryon is adamant that he doesn’t want anyone to get even with the Shepards, thinking that it only leads to a cycle of people fighting each other. Bryon then returns home, and Cathy visits him there. Bryon tells her that he loves her, and that he has a lead on M&M. After a few days Bryon feels better; he visits Charlie’s grave and thanks Charlie for saving his life.
Two nights later, Bryon and Cathy go to the hippie house, where they discover M&M on a very bad drug trip. He is having terrifying hallucinations and had been trying to jump out a window all day. Bryon carries him into the car, and he and Cathy meet her father at the hospital. The doctor tells Cathy, Mr. Carlson, and Bryon that M&M may never recover from the brain damage that the drug has caused.
Bryon returns home, shaken by the incident. He looks under Mark’s mattress for a cigarette to calm him, but instead he finds a bottle of pills. Suddenly, he realizes that Mark has been selling drugs. Thinking about M&M’s bad trip, Bryon calls the cops on Mark. Soon after, Mark returns home, and Bryon tells him about M&M and confronts him about the drugs. Mark claims that he never sold the drugs to M&M. He justifies his actions by saying anyone who wants drugs could get them, and so he might as well make money. Bryon tells Mark that he called the cops, and Mark is shocked. The cops arrive and arrest Mark after Bryon describes all the crimes that Mark had committed.
The next morning, Bryon grapples with whether he did the right thing. When Cathy visits him, he is rude to her, presuming that she is happy now that Mark is out of the way. He promises to call her, but he knows that he doesn’t love her anymore. Bryon testifies in Mark’s trial, and the judge sentences Mark to the state reformatory for five years. Bryon tries to visit him, but he hears that Mark is making trouble at the reformatory. Bryon continues working, and he hears that Cathy is now dating Curtis.
At the end of the summer, Bryon is finally able to visit Mark. Mark says that he hates Bryon, and that he no longer thinks of them as brothers. Bryon thinks that Mark would have killed him if he could. Bryon explains that he hasn’t visited Mark again. He wonders what he could have done differently. He wishes he were a kid again, back when he felt surer of himself and had all the answers.
