After the death of his brother Girón, Pacheco abandons the enriched side and returns with the nobiliary League attracted by Carrillo, who does not hesitate to offer one of his main ambitions: the Order of Santiago. The war intensifies and the two rival armies are summoned in a crucial battle: that of Olmedo. Isabel and Juana pray in Segovia in the same room watching the men go to war, but one for her husband and one for her brother, rivals on the battlefield. In the case of Isabel, the fear is great, knowing that Alfonso, grown by the flattery and lies of Pacheco, is prepared to enter into battle. The battle of Olmedo, equalized, will be decided unexpectedly by the abandonment of it by King Henry, impressed by the carnage.This flight gives the victory to the side of Alfonso, turning him into a hero, believing all that he really fought and not Gonzalo.