In the strict confines of the Presbyterian vicarage in Cork City, twenty-one-year-old Ruth Musgrave lives a life of isolation imposed by her stern father, Pastor Jacob Musgrave. Forbidden from mingling with local Catholic children, Ruth is sheltered from the world, her life revolving around the church and home. Her ailing mother, too afraid to defy her husband's oppressive rule, urges Ruth to seek refuge with Aunt Sarah in Dublin, warning her to escape before she, too, is trapped forever.

Ruth flees to Ballsbridge, where Aunt Sarah, a Catholic, welcomes her with open arms. It is here Ruth learns that prior to her own birth, her parents had travelled to Canada where they suffered the loss of a baby boy. The family soon returned to Ireland after Ruth's birth, but Jacob never forgave his wife for the loss, nor did he bond with Ruth.

Ruth eventually secures a position in the Keen household, caring for Mr. Keen's bedridden wife, Philomena, under the condition that she conceals her Protestant faith. Despite her hardships, Ruth forms a close bond with Philomena, but when doctors recommend Philomena's move to a private clinic, it means Ruth's dismissal. Even so, she continues visiting Philomena, their bond remaining strong.

Learning of her father's grave illness, Ruth returns to Cork in time to hear his deathbed confession which shocks Ruth to her core. She turns to close friend and her pillar of strength, Conor Ryan, for his support as she is forced to navigate her new truth and dreams of better days ahead.