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