When amateur historian Catherine Corless begins examining records from a former Mother and Baby Home in Tuam, Co. Galway, she stumbles upon evidence pointing towards a deeply troubling past. Refusing to let the questions go, she embarks on a painstaking investigation, putting her in conflict with the Church, State, and local town. As official resistance mounts, and unsettling discoveries emerge, her determination challenges powerful institutions, exposing a hidden chapter of Ireland's past that many would rather keep hidden.