Because she is the princess royal, the infanta feels she cannot openly love Rodrigue, a nobleman of lower rank. She encourages, therefore, the growing attachment between Chimène and Rodrigue. Chimène asks her father, Don Gomès, to choose either Rodrigue or Sanche to be his son-in-law. She awaits the choice anxiously; her father is on his way to court and she will soon hear his decision. Don Gomès chooses Rodrigue without hesitation, chiefly because of the fame of Don Diègue, Rodrigue’s father.

However, a complication soon arises at court. The king chooses Don Diègue as preceptor for his son, the heir apparent. Don Gomès believes that the choice is unjust. Don Diègue was the greatest warrior in Castile, but he is now old. Don Gomès considers himself the most valiant knight in the kingdom. In a bitter quarrel, Don Gomès unjustly accuses Don Diègue of gaining the king’s favor through flattery and deceit. He believes that the prince needs a preceptor who will be a living example of the proper virtues, not a teacher who will dwell in the past. In the quarrel, Don Gomès slaps his older rival. Don Diègue, too feeble to draw his sword against Don Gomès, upbraids himself bitterly for having to accept the insult. His only recourse is to call on his young son to uphold the family honor.

Torn between love and duty, Rodrigue challenges Don Gomès to a duel. After some hesitation because of Rodrigue’s youth and unproved valor, Don Gomès accepts the challenge of his daughter’s suitor. To the surprise of the court, Rodrigue, the untried novice, kills the mightiest man in Castile, piercing with his sword the man whom he respected as his future father-in-law.

Chimène now feels herself in a desperate plight because her love for Rodrigue is mixed with hatred for the murderer of her father. She finally decides to avenge her father by seeking justice from the king. Since she has the right to petition the king, Don Fernand is forced to hear her pleas. In the scene at court, Don Diègue makes a strong plea in favor of his son, reminding the king that Rodrigue did only what honor forced him to do—uphold the family name.

The king is saved from the vexing decision when fierce Moors assault the walls of Seville. Chimène awaits the outcome of the battle with mixed emotions. The army of Castile returns in triumph, bringing as captives two Moorish kings. The man who inspired and led the Castilians by his audacity is Rodrigue. The grateful king gives the hero a new title, the Cid, a Moorish name meaning “lord.” The infanta is wretched. Although her high position will not allow her to love Rodrigue, she can love the Cid, a high noble and the hero of Castile. She shows her nobility, however, by yielding to Chimène’s prior right.

Chimène is still bound to seek redress. The king resolves to test her true feelings. When she enters the throne room, he tells her gravely that Rodrigue died from battle wounds. Chimène faints. The king advises her to follow the promptings of her heart and cease her quest for vengeance.

Still holding duty above love, however, Chimène insists on her feudal right of a champion. Sanche, hoping to win the favor of Chimène, offers to meet Rodrigue in mortal combat and avenge the death of Don Gomès. Chimène accepts him as her champion. The king decrees that Chimène must marry the victor. In private, Rodrigue comes to Chimène. Indignant at first, Chimène soon softens when she learns that Rodrigue resolves to let himself be killed...