Rodrigo Borgia, Pope Alexander XI, is not yet over the loss of his son, Juan. His powers are threatening to slip from his hands.

When Rodrigo has a man executed for his homosexuality, Della Rovere comes up with a perfidious scheme to eliminate Rodrigo's secretary, Gacet.

By the end of Lent, torrential rains have flooded Rome. Furthermore, the ordinary people feel threatened by a mythical creature with a mule's head.