Actually, in contrast to Father and Some Mother's Son, The Boxer is an entirely fictional story, and only the opening scene is set in Belfast's notorious Maze Prison. Still, prison is a metaphor that hangs over the entire movie. As Danny Flynn (Day-Lewis) is released after serving 14 years for IRA activity, a bride arrives to marry another IRA prisoner. The implication is clear: all life in Belfast is defined, constricted, imprisoned by 30 years of armed conflict.

What that new prison bride is in for is spelled out in a speech by local IRA leader Joe Hamill (Brian Cox): prisoners' wives are a special class of martyrs who are expected to stand by their men. Hamill equates staying faithful to one's husband with staying faithful to the cause.

Hamill's own daughter, Maggie (Emily Watson), is a prisoner's wife. As a teenager, she had loved Danny Flynn, but when he was jailed, she married another man (who was later jailed himself) and bore him a son, Liam (Ciaran Fitzgerald). Now that Danny has returned, she dares not rekindle the old flame, as violation of the code could result in Danny's death or her own.

Yet Danny believes he can put his old life back together without compromising his own sense of honor. A promising boxer in his teens, he longs to return to the ring, where the fighting has rules and where character, not ideology, matters. Through sheer force of personality, he pulls his old trainer, Ike Weir (Ken Stott), out of a gutter of Guinness and rebuilds the gym of his youth, where both Catholics and Protestants used to train. Taking advantage of the recent ceasefire, Danny stages some bouts that bring both sides together in shared civic pride and love of the sport.

Still, his renewed boxing career faces many of the same obstacles that threaten his much more tentatively reignited romance with Maggie. The more militant wing of the IRA, led by Harry (Gerard McSorley), is as resentful of the gym's Catholic-Protestant unity as it is of Danny and Maggie's new closeness. Young Liam is as wary of Danny's new prominence in the neighborhood as he is of Danny's apparent desire to take his father's place in his mother's life. The locals are as suspicious of the police (who donate brand new athletic equipment to the gym) as the police are of them. And even Danny realizes that he may be no more able to keep politics out of the ring than out of his relationship with an IRA leader's daughter and prisoner's wife.

Sheridan and George make their points without subtlety: love is stronger than ideology; peaceful compromise is better than violent radicalism (Harry might as well wear a black Stetson); sport builds character. Still, even the obvious moments are often touching and poignant: the Catholics hesitantly welcoming Protestants back to the gym for the first time in 30 years, a child at the gym asking the meaning of the word nonsectarian, Danny explaining how good it is to feel pain after 14 years of feeling nothing, and the entire series of awkward glances and brief mutterings that constitute Danny and Maggie's courtship.

What makes the film work, despite its familiar trappings, are the performances of Day-Lewis and Watson. Day-Lewis is very credible as a boxer, having physically transformed himself with his usual Method obsessiveness into a craggy, chiseled scrapper. (Call it My Left Hook.) Head-butting his way through the picture, he conveys with a grimace all that his laconic dialogue leaves unsaid. Watson, too, is reined in (especially compared to her all-stops-pulled-out debut in Breaking the Waves), making it seem like an act of courage just to thaw slowly, as she does over the course of the story. Theirs is the most adult romance of any recent film, as their shared awareness of a lifetime of consequences and costs plays out continuously on their faces.