The film chronicles the life of a working-class Ulster Protestant family from the perspective of their nine-year-old son Buddy (Jude Hill) during The Troubles in Belfast, Northern Ireland. Buddy's father Pa (Jamie Dornan) works overseas in England, while the family-Ma (Caitríona Balfe), elder brother Will (Lewis McAskie), and paternal grandparents Granny (Judi Dench) and Pop (Ciarán Hinds)-live in Belfast.During the August 1969 riots, a group of Protestant loyalists attack the homes and businesses of Catholics on Buddy's street. The residents of the street set up a barricade to prevent further conflict and Pa returns home from England to check up on the family's well-being. Pa has to go back eventually and the extended family is coming to Belfast to meet him. Buddy is not happy that Pa wont be manning the barricade to defend the street. The family attends church, where the minister (Turlough Convery) delivers a harsh fork in the road speech; the rhetoric is continually reflected upon by Buddy throughout the film. Buddy develops feelings for a fellow high-achieving Catholic classmate, Catherine (Olive Tennant), and they eventually become friends. Buddy is head over heals in love with her, and discusses his feelings with Pop, who encourages him to find a way to be with Catherine (after school or during school activities) Buddy and his cousin Moira discuss if it is possible to decipher Catholics and protestants from their names.. and what to do if someone approaches you and asks if you are a catholic or a protestant.. Ps is friends with the locals on his street, including Catholics like Mackie (Gerard Horan), McLaury (Conor MacNeill) & Mr Kavanagh (Drew Dillon)Local criminal and sectarian rabble-rousing person Billy Clanton (Colin Morgan) approaches Pa demanding his involvement in "the cause" with either cash or kind; when Pa refuses, he becomes aggressive and continues to incessantly approach Buddy. Pa tells Buddy and Will not to get involved with anyone they don't know. Pa continues his job in England and only comes back home sporadically during some weekends. Meanwhile, the family struggles to pay off their accumulated tax bill (Pa spends all his earnings on horse races). Ma writes to the tax authorities insisting that Pa is in the clear with all his tax payments. This prompts the tax department to dig deeper into Pa's account and send another 572 pounds bill to Pa. Pa dreams of emigrating to Sydney or Vancouver, a prospect met with distress from Ma. Buddy starts a class project with Catherine to showcase how man got to the moon and back. Billy continues to pester Pa to contribute to the "cause". However, she can no longer deny the option of leaving Belfast as the conflict worsens and Pa is offered a promotion and housing deal in England from his employers. Ma is still distressed at leaving Belfast as she and Pa have lived here all their lives. They know everybody on their street and the streets around them. The whole neighborhood takes care of their boys and they can play wherever they like. Ma knows that England will hate them for their accent and their boys wont be as safe. At Christmas, they attempt to discuss the matter with the boys, but Buddy breaks down at the thought of leaving.Buddy and his cousin Moira (Lara McDonnell) attempt to steal chocolates from a sweet shop (belonging to Mr Singh), but the plan goes awry. When later questioned by the police, he does not reveal his co-conspirators. Following this, Moira recruits him into her local gang, who turn out to be Ulster loyalists that loot a supermarket during a riot. A reluctant Buddy is coerced into stealing a box of laundry detergent before he returns home and informs Ma of his activities. Ma berates him and drags both Buddy and Moira back to the ongoing looting in order to return their stolen items.Billy then appears and takes them hostage as leverage for his own escape. Pa, Will and the British Army arrive at the scene to end the riot. This initiates a standoff with Billy who attempts a shootout until Pa and Will manage to disarm him. He is then promptly arrested and swears retribution.Realising they are no longer safe in Belfast, the family decides to leave for England. Pop passes away. Before departing, Buddy bids farewell to Catherine. He later laments whether he could have pursued a future with her despite the fact she was a Catholic. Pa responds that it should not make any difference and, as Granny watches, the family boards a bus headed for the airport. The film ends with Granny being left alone after the death of her husband and the departure of her children and grandchildren.