Sander zu Tiefenbach has to flee to France from the Roman-German King and also Emperor, Otto of Brunswick. He finds good friends among the Cathars and joins them in the fight against the crusaders sent by Pope Innocent III. Meanwhile, his brother Endres zu Tiefenbach, lord of the Erzburg and the surrounding valley, tries to forge an alliance against Raik of Constantia, whose army, led by his son, is standing outside the city gates of Siegen …