In the heart of London, a young boy named Timmy embarks on his new journey as he starts secondary school in Peckham, Southwark, despite hailing from Deptford, Lewisham. His mother pushes him towards this school due to its excellent curriculum, which inadvertently distances him from his old friend Kiron, a known troublemaker. On his very first day, Timmy crosses paths with Marco, and soon after, he connects with two other boys, Dwayne and Hakeem.
Fast forward four years, and the boys find themselves invited to a party by their classmate Karina. Now 15, Timmy is hesitant to attend until he discovers that his long-time crush, Leah, will be there. Meanwhile, tensions rise back in Deptford as the Ghetto Boys face an attack from the Peckham Boys, forcing the former to flee their territory. That same night, Marco tries to enjoy a movie, The Intent, with his older brother Switcher, the leader of the Peckham Boys, but Switcher is called away to deal with the Ghetto Boys seeking revenge. In a chaotic turn of events, the Ghetto Boys are pursued, leading to a confrontation where Galis, the Ghetto second-in-command, is shot in the back by Switcher and left behind when the Ghetto leader, Madder, retreats to evade the police.
At the party, a romantic moment occurs when Timmy shares a slow dance with Leah, only to be interrupted by a fight between Marco and another boy, prompting Karina's father to kick everyone out. Later, after returning home, Marco's apartment is raided by the police, resulting in Switcher’s arrest. The next day, Switcher is released due to insufficient evidence, and Timmy seizes the chance to invite Leah over for a weekend to binge-watch the final season of Game of Thrones. Their connection deepens, leading to their first sexual encounter and the start of their relationship. Meanwhile, Marco's life takes a darker turn when he crosses paths with Kiron, who now goes by the name Killy and is part of the Ghetto Boys; this fateful meeting leaves Marco with a broken arm.
As tensions rise at school, Marco emotionally accuses Timmy of associating with Killy. Their friendship crumbles when Marco insults Leah, resulting in a physical altercation when Timmy retaliates. Fast forward three months, Timmy and Leah are happily celebrating their three-month anniversary, while Marco, Dwayne, and Hakeem keep their distance. Marco’s transformation into a Peckham Boy alongside Switcher marks a significant shift. Tragedy strikes when Timmy is attacked by a gang, leading to Leah’s accidental death as she attempts to save him, hitting her head fatally. In a brutal twist of fate, Timmy discovers that Marco is behind the mask of danger when he unintentionally exposes himself during the chaotic encounter. Marco is subsequently arrested for Leah's murder.
Three years pass, and Timmy, now 18 and a member of the Ghetto Boys, rises to the position of second-in-command after Galis. He becomes the protégé of Madder. Upon Marco's release, he expresses his profound regret for Leah’s death, claiming it was unintentional. Yet, a few days later, Killy ambushes Marco, now bearing the nickname Bricker. Chaos unfolds as the Ghetto Boys clash with the Peckham Boys outside a nightclub. In a brutal fight, Madder is injured, and after a harmful encounter, Timmy finds himself faced with Marco, wielding a gun that unfortunately jams, allowing Marco to escape. Meanwhile, Switcher faces debilitating consequences that leave him dependent on a wheelchair in the aftermath.
A week of violent confrontations ensues, leading to a crucial conversation between Switcher and his cousin Tyrone, who identifies the vulnerability within the Ghetto Boys. As tensions escalate, Madder attempts to steer the Ghetto Boys' course while seeking music opportunities. An argument erupts between Timmy and Madder over a planned attack on Peckham, culminating in harsh words about Leah that push Timmy away.
Eventually, reconciliation occurs between Timmy and Madder, yet tragedy resumes as Killy betrays Timmy, joining forces with Tyrone. In a tense confrontation, Marco lays a perilous plan against Timmy, dousing a van in petrol. In a desperate struggle, Madder fights to rescue Timmy, but ultimately, Timmy makes peace with his heartbreaking fate, succumbing to asphyxiation in the flames. Madder, desperately trying to save his friend, finally manages to extract Timmy from the inferno, but not without paying a heavy price. The police arrive and take Madder into custody.
As the narrative draws to a close, Madder redirects his life towards becoming a youth worker, while Switcher tragically succumbs to his internal battles through a drug overdose, following the arrests of Marco and Tyrone. Timmy receives a funeral fitting for a hero.
In a poignant post-credit scene, Tiny Madder's music finds fame across the UK as he vows vengeance for Timmy’s untimely demise, intending to eliminate all the Peckham Boys.
