Nuremberg around 1473. "You'll regret this!" are the words of Severin Tucher when the twelve-year-old merchant's daughter Marie brusquely rejects his marriage proposal. She has no idea how right he will be. A year later she is hunted by the Inquisition. One of the most zealous inquisitors is Severin Tucher, who is just waiting to take revenge for the humiliation he has suffered. Together with the pickpocket Ullrich, Marie manages to escape from the dungeon. Ullrich takes Marie under his wing and hides her with a friend, the astronomer and mathematician Regiomontanus. Marie is fascinated by his instruments and the observatory on his roof. But the astronomer also seems to be hiding a secret. And is Marie really safe with him?