On 30th January, 1972, the British Army shot dead thirteen unarmed civilians on a civil rights march in Derry, Northern Ireland. Confidence in British justice evaporated among the victims' families when Lord Widgery exonerated the soldiers and blighted the reputation of those killed and wounded. The film follows the families' long search for the truth at the new Tribunal of Inquiry into 'Bloody Sunday' held in Derry and London over a 6 year period until its momentous conclusion on 15 June 2010 when the Inquiry report was finally published