German director Oliver Hirschbiegel, who chronicled the disintegration of the Nazi high command in Downfall (2004), turns to a smaller but comparably gripping tale of violence and retribution, this one set in Northern Ireland. Pivoting from history to speculative fiction, screenwriter Guy Hibbert opens with a 1975 incident in which a 15-year-old Protestant boy assassinated a 19-year-old Catholic boy in full view of the victim’s 11-year-old brother; the narrative then leaps ahead 30 years to an imaginary summit between the two survivors that’s being taped for a TV show. James Nesbitt gives a fine performance as the enraged but fearful brother, and Liam Neeson holds his own as the reformed shooter, who’s had the gall to become philosophical about the whole thing. The run-up to their meeting is more arresting than what follows, but the movie is unusually honest in recognizing the limits of forgiveness. R, 90 min.