West Belfast 1992. Three teenagers steal cars, perform stunts, and try and ram RUC armoured patrol cars. The diminutive Sean, whose dead brothers were in the IRA, lives with his mother and sister; Frances is a very bright sixth former; the hapless, myopic Desmond 'Marley' Hagen lives with his blind father and very respectable mother.

Their joyriding gang join a late night driving display, interrupted by an outraged local resident who throws a brick before being attacked by the mob of youths. Despite hearing of the IRA's displeasure, they steal cars from a hospital and drive out into the hills. Frances asks Sean whether he would follow her to England if she went to university there. But he doesn't want to leave home.

Two local priests hold a community meeting about the joyriding problem, while gangs race around the venue. RUC officers observe the scene but do not intervene. A former IRA chief of staff, Reggie Devine, and his cronies ridicule the priests' calls for tolerance, instead promising violent direct action. Meanwhile, IRA supporters running the local youth club attack Sean and humiliate Frances and her friend Mary. In revenge, Sean and Marley throw turnips at the youth leader's windows. Vigilantes come round for Marley and haul him to Devine, who orchestrates a terrible beating. Sean is spared because of his Provo connections. Frances tells him she would like to go back to just the three of them having fun. The other gang members vandalise the IRA men's cars but Sean is caught in a stolen car by RUC men who beat him up, simulating car accident injuries. The police ask him to become an informer but he refuses.

The IRA moves to crush the gang. Mary is tied up in public and has paint poured over her head by women IRA supporters. Two other boys are kneecapped but Sean, hidden by his mother and sister, is given 24 hours to leave the country.

The rest of the gang sneak Marley out of hospital and start racing and showing off. Scared, Frances gets out. The car rams an army roadblock and its passengers are shot dead by soldiers. Reggie Devine goes to Sean's house and announces that his banishing order has been lifted but Sean contemptuously tells him he is going to England anyway. The priest drives him to the airport past the wreckage of his friends' car.