Reuben James, Denzel Washington a Black British man born in Saint Lucia and raised in the United Kingdom, joins the army paratrooper regiment. In 1979, he is attacked by IRA militants while leaving a pub in Northern Ireland, and is saved by fellow soldier and Londoner fish. Later in 1982, Reuben and his friends fish and Londoner Bob Harper fight in the Falkland Islands. There, fish loses his leg. In 1988, Reuben leaves the army and returns to his poor London neighbourhood. Reuben's longtime friend Colin is now a kingpin, and offers to make Reuben a part of his drug dealing operation, but Reuben declines.
Fish is now a gambler who cheats on his Irish pregnant wife, Debbie Stella Gonet. He and Reuben attempt to celebrate the latter's return to civilian life at a nightclub, but are turned away by the bouncer. The two then spend the night drinking at Fish's flat. Returning home, Reuben finds his flat being burgled by children Oscar Anselm Peters and Hayley. Reuben threatens Oscar, who points out Hayley's flat. Hayley's mother, Stacey Amanda Redman is there and gets Reuben to leave. On his way out, Hayley comes home wearing Reuben's paratrooper beret, which he takes back. Stacey eventually finds Reuben's campaign medals and returns them to him.
Reuben begins to look for a civilian job, to no avail. Meanwhile, Fish wins a lot of money by gambling and buys two tickets to Paris. He plans to take Reuben with him as a thank-you for covering an earlier debt with Bob, who is now a policeman. Later, at a party on the estate, Reuben encounters Stacey; the two dance, and Reuben walks her home. En route, they are subjected to racist insults from officers. Reuben later returns to the party, which is raided by the police. Several of his friends, including a man named Lynford Geff Francis, get arrested, but Bob tells him not to get involved. The next morning, Debbie gives birth early. Reuben takes Fish to the hospital, and Fish gives him both tickets, saying that he will not be able to go.
Reuben takes Stacey and Hayley to a funfair; there, he asks Stacey to accompany him to Paris. Stacey agrees until she sees Reuben playing a shooting game. This brings back memories of Hayley's father, a gangster who kept guns in the house, including in Hayley's cot. Reuben comforts Stacey and says that he is done with guns. Stacey later offers to get Reuben a job driving a minicab. When they return to the estate, there is a commotion happening. Lynford has thrown a brick at a police car, killing Constable Harry Brian McDermott. Racist officer Kilcoyne George Baker asks Reuben whether he knows anything, which he denies.
While preparing for the trip to Paris, Reuben applies for a new passport, but is rejected. Since he was born in St. Lucia, a change in British nationality law has stripped him of his citizenship. Disillusioned, Reuben agrees to work as "muscle" for Colin. Carrying a gun, he runs into Stacey. After discovering it, she leaves, furious. The police later arrest drug dealer Sadiq Jimmi Harkishin, whom Colin has set up with Reuben's help. Returning to the estate, Reuben gives Colin back his gun and quits. He later finds Fish distraught after Debbie has left him and taken the children to Ireland. Giving Fish money, Reuben tells him to go after her.
Knowing about the deal with Colin and Sadiq, Kilcoyne later threatens to send Reuben to jail unless he says who killed Harry. Reuben reluctantly gives up Lynford. Subsequently, wanting to leave behind his current life, Reuben gets a St Lucian passport and a ticket to St Lucia. Meanwhile, Lynford and others gather weapons, preparing to fight the police. From a walkway, someone throws a Molotov cocktail, starting a riot.
With his bag packed, Reuben runs into Fish in the lift. They later find Lynford hiding from police on the ground floor. Racist policeman Challoner Craig Fairbrass and another officer then appear. Challoner panics and shoots Fish dead; Kilcoyne then runs in. Distraught, Reuben goes to Fish's flat to retrieve his rifle. As the riot subsides, he shoots Challoner dead. Reuben soon gets in the sights of a hesitant police sniper, who is actually Bob. After being ordered to take the shot, Bob fires.
