The film is set in 1521 Antwerp, during the early years of the Reformation in a Europe plagued by religious warfare. It is the narrative of Falko Voeten, a twelve-year-old printer's kid. A letter written by Maarten Luther is printed by Falko's father, Klaas Voeten, an Inquisition printer. Threatened by the Inquisition but helped by Marieke, a Catholic orphan from the sewers, Falko must save his father from execution for heresy.