Seventeen-year-old Maverick Malcolm Carter, known as Mav, plays basketball at Rose Park with his cousin, Dre, his best friend, King, and Shawn, Rico, P-Nut, and Junie. All are members of the gang, or “set,” called the King Lords. Mav lives with his mother, Faye, in Garden Heights. His father, Adonis, one of the original King Lords, has been in prison since Mav was seven. There are several levels in the King Lords. Mav and King are “li’l homies,” members who sell only weed and help with initiations. Older members, including Shawn and P-Nut, are known as “big homies” who get to sell harder drugs and fight with their rival gang, the Garden Disciples.
A year ago, Mav had a one-night stand with King’s sometimes-girlfriend, Iesha, who later gave birth to a boy she named King Jr. After the basketball game, Mav and Faye meet Iesha at a clinic, where they learn that Mav, not King, is the father of the baby. Iesha abandons King Jr. with Mav and disappears. Later, Dre, who has cleaned up his lifestyle to take care of his fiancée and baby, Keisha and Andreanna, tells Mav he must make similar changes now that he’s a father. He makes Mav promise to stop dealing, helps Mav get a part-time job working for Mav’s neighbor, Mr. Wyatt, and drives Mav to his girlfriend Lisa’s house so he can come clean about the baby. Upon hearing the news, Lisa breaks up with Mav.
At school, Ant, a Garden Disciple, warns Mav to tell Dre to watch his back because he’s been racing his car in their territory. Later in the day, Mav and King confront a guy named Red who sold Mav fake Air Jordans, but Red refuses to refund Mav. For the next month, Mav focuses on school, working in Mr. Wyatt’s garden and grocery store, and caring for his son, whom he’s renamed Seven. One night, Dre surprises Mav with a water gun fight and pizza, which they eat in Dre’s car, even sharing a piece with Bus Stop Tony, a local addict, who happens to walk by. While Mav is in the house checking on Seven, gunshots echo in the street. By the time Mav gets back to the car, Dre is dead. At Dre’s funeral, Mav tells Shawn, one of the set’s big homies, that he suspects Ant killed Dre, and Shawn promises to look into it. Lisa and Mav then walk to her house, where they end up having unprotected sex.
One Friday night, Mav, King, Rico, and Junie go to a football game, where Ant is shot and killed in the parking lot. Three weeks after Dre’s funeral, Lisa and Mav find out she’s pregnant, but Lisa refuses to get back together with him as he’s in a gang and she wants someone dependable. The day before Thanksgiving, Faye and Mav visit Adonis in prison so Mav can tell him about Lisa’s pregnancy. Adonis wonders why Mav keeps making “stupid” mistakes, to which Mav replies that it was Adonis’s stupid mistake that landed him in prison. Later, Mav learns that Lisa’s mother threw her out and she’s living with her best friend, Tammy. At Lisa’s first doctor’s appointment, Mav feels humiliated that he can’t afford her $20 co-pay; he makes up his mind to start dealing again and reaches out to King.
While visiting Lisa at Tammy’s, Mav notices that Red, Tammy’s sister’s boyfriend, is wearing Dre’s gold watch, the same watch Dre had on the night he was killed. When Red realizes that Mav recognizes the watch, he abruptly leaves the house. Mav becomes obsessed with Red and keeps making mistakes at work. Mr. Wyatt, understanding the pressures put on Mav by fatherhood and the lure of the set, reminds Mav that he has the power to forge his own path in life. When Mav tells P-Nut, the new head of the King Lords, about Red, P-Nut insults and dismisses him. Mav suddenly understands that the set doesn’t offer him the support and safety it once did.
Soon, Mav flunks out of school. While getting drugs at King’s house, he tells King that he thinks Red killed Dre. King implies that Mav must take care of business himself and later gives him a gun. At home, Mav pretends to go to school every day but instead follows Red to memorize his daily routines. One afternoon, after Mav and Lisa take a tour of Markham State College, which Mav arranged as a surprise for Lisa, they meet Keisha at a restaurant. Knowing Keisha was on the phone with Dre when he was shot, Mav asks her to share what she heard. He learns that Bus Stop Tony returned to the car to ask Dre for money. When Mav questions Bus Stop Tony later, Tony describes the killer’s car, and Mav knows for sure that Red’s guilty. One night, Mav goes to where he knows Red will be. He creeps up on Red from behind and holds the gun to Red’s head. Ultimately, he’s unable to pull the trigger, and he runs straights to Lisa’s, where he tells her everything. As Lisa holds him, he decides to make changes in his life.
Back home, while Mav gathers up his drug stash to return to King, some falls into the toilet. Mav panics, knowing he’ll still owe King the cash for what’s lost. The next morning, he gives King back the gun and what’s left of the drugs. King becomes infuriated that Mav lost him money and warns Mav that he’ll get even one day. King drives away, and Mav lets himself into Mr. Wyatt’s backyard to admire the roses he planted, roses that Mr. Wyatt explained could bloom even under harsh conditions. Mr. Wyatt joins him. When Mav informs him that he’s going to get his GED, Mr. Wyatt offers him a full-time job. Weeks pass, and Mav and Lisa learn they are having a girl. Lisa notices all of the changes Mav’s made in his life to prove to her that she can depend on him. As they sit on Mav’s porch, they think of what they might name their daughter.