Northern Ireland, 1979. Reuben, Fish and Bob, squad-mates in the Parachute regiment, stumble from a pub. While Reuben drives Fish home, they are attacked by paramilitaries. Reuben is injured; Fish saves his life.

The South Atlantic, 1982. Fish and Reuben prepare to deploy in the Falklands.

1988. Reuben, now discharged, returns to his flat on a London housing estate. On the way, he bumps into old friend Lynford, the neighbourhood wheeler-dealer. He is also stopped and questioned by racist police officer Challoner. Challoner's boss, Kilcoyne, intervenes, realising Reuben is ex-army.

At home, Reuben is visited by Colin, another old friend. Colin offers Reuben unspecified work; Reuben refuses. Reuben visits Fish, his wife Debbie, and their children. Fish lost a leg in the Falklands war and is struggling financially. When Bob (now a policeman) turns up demanding Fish pay off a debt, Reuben provides the money; Fish is humiliated.

Reuben discovers a teenage girl, Hayley, and her younger brother, Oscar, burgling his flat. He makes Oscar lead him to his own flat, where he has an angry confrontation with their mother, Stacey. Later, an apologetic Stacey returns Reuben's medals.

Reuben meets Lynford. Challoner arrives. He roughs up Lynford and, when a bystander attempts to intervene, pulls a gun. Kilcoyle arrives, and Challoner hastily conceals the gun. Kilcoyle asks Lynford about his whereabouts a few days ago. Lynford volunteers Reuben as his alibi; Reuben supports him.

Colin shows Reuben around his sports centre. Reuben notices a gun in the glove compartment of Colin's Porsche. Colin claims his business is legitimate and offers to make Reuben his partner. Reuben refuses.

Fish, Bob and Reuben go to a party, where Reuben dances with Stacey. Walking Stacey home, Reuben sees police raiding the party. Lynford is led away in handcuffs. Bob warns Reuben not to get involved.

Reuben, Stacey and her children visit a funfair. Reuben offers to take her to Paris; she agrees. But seeing Reuben using a rifle range, she becomes distressed, citing her ex-partner's involvement with guns. Reuben promises her he's hung up his guns for good.

Returning to the estate, they see three youths - one wearing a jacket with a distinctive 'HBC' logo - drop a concrete block on a police car, killing well-liked neighbourhood constable Harry. Questioned by Kilcoyne, Reuben denies seeing anything.

Reuben is shocked to find his passport renewal application refused. Since St Lucia, his birthplace, is now independent, he is no longer considered a British citizen. Reuben drowns his sorrows with Fish. Returning to Fish's flat, they find bailiffs at the door. Reuben sends them packing.

At home, Reuben sobers up and gets ready to go out. Stacey, realising he has a gun on him, leaves in disgust. Reuben provides security for Colin's drugs deal. Subsequently, Colin signals to waiting police officers, who apprehend his contact. Colin pays Reuben £5000.

Visiting Fish's flat, Rueben is nearly shot. Fish, in despair, is defending his home with his service rifle. Debbie has returned to Ireland with their children. Reuben gives Fish the £5000, along with a sure-fire racing tip. Reuben returns home, where Kilcoyne waits for him. Kilcoyne knows about Reuben's work for Colin, and intends to blackmail him into aiding his investigation into Harry's murder.

Police raid the estate, and tensions run high. Reuben finds a group of youths making Molotov cocktails. He is shocked to see Lynford leading them - wearing the jacket with the 'HBC' logo.

Reuben warns Kilcoyne of the impending trouble. The police launch a massive operation to capture Lynford. Riots start. Reuben heads off with his kit-bag. Meeting Fish, he tells him he is leaving for St Lucia. They run into Lyford. Lynford points a gun at Reuben but Fish surprises him, disarms him and knocks him out. Challoner and a subordinate arrive at the scene and, in the confusion, Challoner shoots Fish. Kilcoyne arrives and confiscates Challoner's gun. Fish dies.

A short while later. Reuben breaks into Fish's flat, taking his service rifle. Back on the estate, rioters and police continue battling. Rueben shoots Challoner. As Reuben walks away, he is tracked by a police marksman: Bob. Bob hesitates for a moment, then, prompted by his superior, opens fire.