Three men drive towards the Spaghetti House restaurant, planning to rob it. The younger two, Wesley Dick and Anthony Monroe, want to back out, but the eldest, Frank Davis, questions their manhood. The men round up the restaurant staff. In the confusion, one escapes and calls the police.

The siege begins. Wesley has no bullets in his gun, and when Frank begins negotiating with the police, the first exchange is an argument about rank, with Frank asserting his superior status. He has already begun improvising the robbery as a military campaign for black liberation.

A few weeks earlier. Frank is released from prison, back into digs run by criminal friends. Alone in his room, he recalls an earlier return to his native Nigeria, where he receives harsh treatment in a mental hospital.

The siege. Members of the newly formed 'Black Liberation Army' attack their hostages for Italy's role in Ethiopia.

The past. Wesley, working in a warehouse, quits his job because of his poetry-hating, racist boss. Wesley has already served time for book stealing. He wants a job in a community centre, which has no funds.

The siege. The BLA demands access to the media. The police provide a radio in exchange for prisoners. Leading black politician Lord Pitt is brought in to negotiate.

The past. Middle-class, university drop-out Anthony has, with Welsley, applied for a grant for a Black Saturday school. He fights with his mother when she hears he would rather go to Ibadan University than return to his medical studies. Meanwhile, Frank is meeting old ex-convict friends. He recalls the racist abuse they received from prison officers.

The siege. A released hostage gives the police vital intelligence. The BLA's demands for the release of two prisoners and a plane are treated with derision, as the police reveal that the two prisoners have already completed their sentences and been released.

The past. Frank is rejected by his regular prison visitor, a beautiful woman, who only visited him for ideological reasons. An angry Frank returns to a gambling den, where he hears about a place in Knightsbridge where £40,000 takings are kept on a Saturday night. Elsewhere, Anthony rows with Sheila, his girlfriend and benefactor, after disappearing for three days. He has attended a Blues dance which was attacked by police. Anthony and Sheila's reconciliation is ruined by the rejection letter for the funding application for Anthony's school. Anthony is broken. Meanwhile, feelings are running high in the community over the raid of the Blues dance. Wesley is especially angry. Feeling powerless, he composes a militant poem before trashing his flat.

The siege. The hostages are beginning to suffer. One man is very ill, and the BLA members, beginning to empathise with these poor southern Italians, release the man.

The past. Frank tells the other two of the £40,000 which will solve all their problems. Anthony doesn't want to go armed. Frank convinces them that a gun is necessary. Other men in the community resent Frank's malevolent influence. They banish him to North London.

The siege. With options running out, the BLA begin arguing among themselves. The young men want to go out in a blaze of glory, taking some policemen with them. Frank wants to go out because the situation is lost. They hold a gun to each other's throats. Frank wins the battle of wills. Anthony calls him a dirty sell-out, before giving himself up. Frank tries unsuccessfully to shoot himself.

At the trial, Anthony is sentenced to 17 years, Wesley 18, and Frank 21 years in prison.