Jackie is a seven-year-old boy living in a city in Ireland who is terrified of his upcoming first confession. He views his home as divided into factions and holds a fearful view of theology shaped by his severe catechism teacher. Because he recently snapped during a dinner dispute and threatened his older sister with a bread knife, he is convinced he is an unforgivable sinner bound for eternal punishment.

Nora is Jackie's older sister who frequently manipulates the adults around her for her own benefit. She flatters her grandmother for money and taunts her younger brother about the severity of the sins he must confess to the priest. At church, she acts deeply pious and emerges from the confessional looking perfectly saintly, contrasting sharply with her cruel behavior at home.

The young priest hears confessions at the local Catholic church. For the terrified children of the parish, he represents the imposing authority of the church and the ultimate judge of their sins. He conducts the solemn sacrament in a dark, tiny, closet-like room that greatly intimidates his youngest parishioners.

Gran is Jackie's paternal grandmother, an elderly widow who recently relocated from a rural farm to her son's city home. She retains her unrefined country habits, often going barefoot, eating with her fingers, and carrying an open bottle of beer. Her complete lack of urban polish deeply embarrasses Jackie, especially when his friends are around.

Mrs. Ryan is an older woman responsible for teaching catechism to the children of the parish. She favors intimidation over inspiration, challenging her young students to hold their fingers over a candle flame to simulate eternal punishment. She dresses perpetually in black and ensures her students are terrified of making an incomplete or dishonest confession.

Jackie's father is a working-class man in the city who has recently taken his aging mother into his home. He is strict and reactive, punishing Jackie physically for acting out against Gran and Nora. He makes no effort to listen to his son's perspective regarding the dinner dispute.

Jackie's mother manages the household and shares her son's distaste for her mother-in-law's unsophisticated country habits. Despite her sympathy for Jackie's frustration with the terrible meals and lack of manners, she is passive and only steps in after her husband has already severely disciplined the boy.