It has snowed. A white shimmer lies on the fortress walls as Barthel reaches Wartburg. As feared, he brings Luther the news that radical forces are threatening his Reformation. Back in Wittenberg, Luther manages to put his writings and sermons into practice, while at the same time his opponents are gaining strength. Above all, his former companion Thomas Müntzer calls for an uprising against the secular authorities, putting many people in danger. As the situation escalates, Luther decides to take up the fight against Müntzer.