Jeremy Irons returns in season three of THE BORGIAS in his role as Pope Alexander. After surviving a near fatal assassination attempt, he responds with an iron will by ruthlessly purging the Vatican of anyone who might be disloyal to him. Alexander's true master plan is to establish the Papacy as a hereditary monarchy across the heart of Italy – for father and son to rule the world. But he must come to accept that his children are independently ready to wield their own power. Cesare, now the military prince and daring guerrilla fighter, is so eager for action that he comes perilously close to war with his own father's army. His sister Lucrezia is equally frustrated when her husband, the Neapolitan prince Alfonso, proves to be a disappointment. Feeling desperate to secure a future for herself and her child, she enters the dangerous fray of Neapolitan politics and learns the art of poisoning. As their passions grow, and as mistrust of all others becomes more ingrained, the siblings finally give in to their desires and embark on a passionate incestuous relationship. With both that scandalous secret and the unspoken agonies of Juan's death lingering between them, the family is riven by paranoia and suspicion.