Fernando sends his son, Sancho, with a small army to Zaragoza to confront his brother, Ramiro, the King of Aragon. Before leaving with Sancho, Ruy reveals to the King that Flaín tried to kill him. Fernando starts to investigate who betrayed him. Meanwhile, Ruy leaves León ignorant to the fact Flaín sent a hitman within the troop to kill him.

The Castile tropos with Sancho and Ruy fight an outnumbered battle against the Aragonese. When all seems lost, the outcome seems totally unexpected. In León, Fernando discovered who was conspiring against him.

Alfonso, following Urraca’s advice, has one last tempting card up his sleeve to get Ruy to stay in Leon by his side: breaking off Jimena’s betrothal to Orduño and blessing her marriage to Ruy. Ruy will get everything he wants, but in exchange he will have to betray Sancho. Meanwhile, the Arabs, who are looking to destabilize the Christian kingdoms, tell Sancha that the King was poisoned.

After Ruy’s decisive intervention in the battle, Sancho of Castile takes Galicia from his brother García. But this does not bring peace to the Iberian Peninsula. On the contrary: the final battle between Leon and Castile is approaching. Meanwhile, Ruy is forced to betray Amina.