The film follows the challenges faced by a working-class Ulster Protestant family, seen through the eyes of their nine-year-old son, Buddy, during the tumultuous period known as The Troubles in Belfast, Northern Ireland. Buddy's father, Pa, works overseas in England, leaving the rest of the family—Ma, his elder brother Will, and their paternal grandparents, Granny and Pop—to navigate life back home in Belfast.
As August 1969 riots erupt, a group of Protestant loyalists violently target the homes and businesses of Catholics on Buddy's street, prompting residents to erect barricades to fend off further attacks. Amidst the chaos, Pa returns from England to ensure his family's safety but must eventually leave again, much to Buddy's dismay, as he feels the weight of the impending conflict.
During a church visit, the minister, Turlough Convery, delivers a stern speech about the crossroads facing the community. This resonates deeply with Buddy, who grapples with his feelings for his talented Catholic classmate, Catherine. As they forge a friendship, Buddy finds himself hopelessly enamored, confiding in Pop, who encourages him to seek out moments to bond with Catherine, whether in or out of school.
Amidst conversations with his cousin, Moira, Buddy explores the distinctions between Catholics and Protestants, while navigating friendship with local boys, including Catholic friends like Mackie and Mr. Kavanagh. Tensions rise further when Billy Clanton, a local criminal, harasses Pa for money or support in "the cause," escalating the fears for Buddy's safety. Throughout this period, Pa remains preoccupied with work and increasingly distant from his family.
As the family's financial burdens mount, tensions between Ma and Pa strain their relationship. Pa dreams of emigrating to Sydney or Vancouver, a notion that terrifies Ma, who feels a deep-rooted connection to Belfast and the community that has helped raise their boys. Christmas brings a moment of crisis as they discuss the possibility of moving, with Buddy breaking down at the thought of leaving his home and friends.
In a misguided attempt to bolster their rebellious spirit, Buddy and Moira embark on a plan to steal sweets from a local shop, which spirals into chaos as they become embroiled in rioting alongside loyalists. Their escapades lead to an intense confrontation with Billy, which culminates in a standoff involving Pa, Will, and the British Army. With the situation deteriorating, and safety compromised, the family ultimately decides that a move to England is their best option.
As they prepare to leave, Buddy bids an emotional farewell to Catherine, grappling with thoughts of a future filled with possibilities, despite their differing backgrounds. Pa reassures him that love knows no divisions, while a deeply saddened Granny faces the loss of her loved ones and the passing of Pop. The film poignantly concludes with the family boarding a bus to the airport, leaving behind a fractured community, as Granny is left alone to contemplate the void created by their departure.
