The film is set in west Belfast in the early years of the conflict. Gary, an English lad from Derbyshire who has joined the Parachute Regiment, is left behind by his retreating unit. He finds himself in a no-man’s-land where “the enemy within” appears to apply both to friend and foe. It is a world in which the authorities are running high-level informers and supplying arms to loyalist paramilitaries to maintain a deniable, proxy war.