Albano 1525. Princess Elena Campireali, after receiving a severe education in the abbey of Castro, is betrothed to Prince Savelli who in exchange ensures the cardinal's investiture to Fabio, Elena's brother. Elena however falls in love with Giulio Branciforte, a mercenary in the service of Cardinal Colonna, who wants to become Pope at all costs. After a series of vicissitudes, Elena marries Savelli believing Giulio dead, in 1527, German serfs, mercenaries known as Lanzighenecchi (Landsknechten) descend to Italy and attack Rome, causing chaos and disorder.