It’s the mid-11th Century. Ruy es a young man who has just been named squire to Prince Sancho, King Fernando of León’s eldest son. One night he discovers that someone he loves is involved in a conspiracy to overthrow the King. From then on, Ruy is caught between his loyalty to duty and to his heart.

After the assassination of Flaín, the Count of Leon, many point at Ruy as the culprit. Meanwhile, the one from Vivar is forced to go back to Zaragoza, where he was sentenced to death for having lain with Amina, the Emir’s daughter. In Leon, Urraca finds out that Jimena and Ruy are in love, and schemes a plan to gain benefit from this information.

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.