Act I - The Duel
Scene 1 Spain is a country divided by civil war. The commander of the royalist troops, Count di Luna is in love with a lady-in-waiting to the Princess, but she does not respond to the Count's approaches. An unknown troubadour has been serenading Leonora for a while, and the jealous Count desperately wants to capture him. Count di Luna's men are guarding the Aragonian Palace, and captain Ferrando, in order to keep the soldiers awake, tells of a Gypsy woman's terrible deed. She was sentenced to be burnt alive at the stake for bewitching the Count's young brother. In revenge, the Gypsy woman's daughter abducted the child and, as the legend goes, threw him into the fire at the place where her mother had been killed. The burnt remains of a child's skeleton were found there, and Count di Luna's father soon died in his sorrow. As he was dying, the old Count, hoping that the burnt bones were not his son's, made his son swear to seek out the woman. They never found the Gypsy girl though.
Scene 2 In the garden of the palace, Leonora confesses to her friend Ines that she has fallen in love with a mysterious man she met before the war. It is he who serenades her as a troubadour every night. When they leave, Count di Luna arrives, and is almost maddened by his desire for Leonora. As he is walking towards her door, the troubadour's song is heard in the darkness. Leonora rushes out to greet the singer, but she rushes into the Count's arms by mistake. The troubadour appears and reveals his identity: he is Manrico, leader of the army of the rebels. The furious Count challenges him to a duel to the death.
Act II - The Gypsy Woman
Scene 1 Manrico is about to win the duel, but, influenced by some strange instinct, steps back from the last and lethal thrust and leaves the Count alive.
The war continues, and the royalists triumph in the final battle. Manrico is seriously wounded, but his mother, the Gypsy Azucena, takes him from the battlefield to the mountains and cures him in a camp. She is the Gypsy girl Count di Luna seeks. Her life is haunted by the memory of her mother's death and thirst for vengeance. Azucena begins to tell her terrible story.
She abducted the old Count's young son, but the boy, who she later killed, was her own son. When Manrico wants to know who he really is, Azucena gives evasive replies; it is only maternal love that she has always showed to him and Manrico should keep his oath to take revenge on the di Luna family. He learns that Leonora is going to a monastery because she believes that her beloved has died in battle and wants to escape the Count. He does not listen to his mother's advice and leaves for Leonora immediately. Azucena sets off too.
Scene 2 Di Luna wants to attack the monastery with his troops and abduct Leonora by force. The girl is being prepared to take a solemn vow to become a nun when the Count tries to abduct her, but Manrico and his men prevent him from doing so. A fight breaks out, and the two lovers escape in the turmoil.
Act III - The Son of the Gypsy Woman
Scene 1 Count di Luna and his army is about to attack the fortress where Manrico and his love have taken refuge. Ferrando drags Azucena to the scene; she has been captured near the camp. When she hears the name of di Luna, Azucena's reaction arouses Ferrando's suspicion and he recognises the murderer of the Count's brother in her. When Azucena cries out to Manrico, the Count realises how he might lure his enemy out of the castle… He orders his men to build a pyre to burn Azucena on the spot.
Scene 2 In the fortress, Leonora and Manrico are preparing for their wedding. The girl is terrified as a fight with di Luna seems unavoidable, and Manrico's troops are largely outnumbered. The man swears eternal love to her. When they hear that Azucena has been captured, Manrico launches an attack on the Count and his troops.
Act IV - The Punishment
Scene 1 Manrico and his army are defeated; he and Azucena are imprisoned in da Luna's castle. Leonora, who has managed to escape with Manrico's lieutenant, arrives at the castle. She says a prayer for the salvation of her beloved. The voice of a troubadour is heard from the castle. Count di Luna orders Manrico and Azucena to be executed. In exchange for the freedom of her love, Leonora offers herself to the Count, who accepts the proposal unaware that his beloved has taken slow-acting poison.
Scene 2 In the dungeon, Manrico is trying to console Azucena, who is terrified of her imminent death by fire. Leonora rushes in and urges Manrico to flee. He realises his beloved has saved him; he rejects the girl, as well as the Count's pardon. But the poison begins to work, and Leonora dies in her lover's arms - before the eyes of the Count. Di Luna has Manrico executed.
Azucena cries to the heavens: her vengeance has been fulfilled - the Count has killed his own brother.