Isabel and her brother Alfonso live a happy life in Arévalo with their mother Isabella of Portugal, King John II of Castile's widow.

The nobles begin to act on their plot to dethrone Isabel's half-brother Henry.

As the Civil War brings chaos and anarchy to Castille, Isabel finds out her half-brother Henry promised her to a man she does not love.

After his brother Girón dies, Pacheco defects from Enrique's side; Carrillo offers him the Order of Santiago.

Alfonso's death deeply affects Isabel; Carrillo believes the war should continue and Isabel should be crowned as queen.

Negotiations in Guisando do not come to fruition; as feared by Chacón and Cárdenas, Enrique's promises are not honored; the Mendozas publicly protect the rights of the king's daughter.