Part One: The Duel
Ferrando, on guard duty late one night in a Spanish palace, keeps his soldiers awake by telling them the spooky story of the two sons of the former Count di Luna (father of the current Count). One morning long ago an old gypsy hag was discovered casting a spell on the Count’s younger boy, still an infant; he took sick, so the witch was burned at the stake. But in revenge, the witch’s daughter kidnapped the Count’s baby, and the charred remains of a child were discovered where the witch had been executed. The old Count didn’t believe his son had been killed, and on his deathbed he made his surviving son swear an oath that he would never give up the search for his younger brother. Ferrando insists that, even after all these years, he would still recognize the witch’s daughter.
In the palace gardens, Leonora, a lady-in-waiting to the princess, tells her friend Inez about a knight who has been serenading her. Leonora professes her love for the mysterious troubadour.
Count di Luna, who loves Leonora, approaches her balcony; but at that moment the troubadour is heard approaching, serenading his beloved. Leonora rushes out and greets the Count, mistaking him for the troubadour. The mysterious troubadour finally reveals his identity: he is Manrico, leader of the rebel army. The rivals challenge each other to a duel.
Part Two: The Gypsy Woman
Dawn rises on a gypsy camp in the mountains; the gypsies begin their day, singing the Anvil Chorus. Azucena, an old gypsy woman, sings “Stride la vampa,” a haunting description of a woman being burnt at the stake. The gypsies leave alone her with Manrico, who is in the gypsy camp recovering from his wounds; Azucena, his mother, discovered him left for dead on a battlefield and has been nursing him back to health. He asks her why she always sings “Stride la vampa.” Her mother, she explains, was burnt to death by the soldiers of Count di Luna; Azucena watched her mother die in agony and heard her scream, “Avenge me!” Azucena then abducted Count di Luna’s infant son, García, intending for him the same horrible fate her mother had suffered. Carrying her own young son as well, she brought García to the still-burning stake, but as she was placing him in the flames, she hesitated, moved to pity by the boy’s cries. But the sound of her mother’s screams echoed in her mind, and in her confusion and anguish she grabbed hold of the child and blindly pushed him into the flames. When she recovered her senses, she discovered that she had mistakenly killed her own son.
Manrico is puzzled: then who is he? Azucena insists that he is her son. She begs Manrico to avenge his grandmother by killing the younger Count di Luna, and asks why he failed to kill his rival when they fought a duel. Manrico explains that at the fatal moment, a mysterious power stayed his hand.
A messenger brings Manrico the news that his beloved Leonora, believing him dead, is going to enter a convent. Despite Azucena’s entreaties, he rushes off to find Leonora.
Overcome with passion for Leonora, Count di Luna determines to abduct her before she enters the convent. Just as he’s about to do so, Manrico arrives and takes Leonora off with him instead.
Part Three: The Gypsy Woman’s Son
Di Luna intends to attack the fortress where Manrico has taken Leonora. Soldiers bring in Azucena, who has been apprehended, wandering nearby searching for her son. Ferrando recognizes her as the killer of the Count’s baby brother. “Manrico, my son, save your unhappy mother!” Azucena blurts out, and Count di Luna is delighted to discover he can simultaneously avenge his brother and hurt his rival by tormenting this prisoner.
Leonora and Manrico are about to be married when news arrives of Azucena’s plight. Manrico gathers his army and rushes off to save his mother.
Part Four: The Torture
Manrico and Azucena await execution in di Luna’s prison. Leonora approaches, determined to save Manrico. She promises herself to di Luna in exchange for Manrico’s freedom. Di Luna agrees to the bargain. While his back is turned, he fails to see Leonora swallow a deadly poison concealed in her ring.
In their prison cell, Manrico tries to comfort Azucena, whose hallucinations and terror are getting worse. Leonora enters and tells him he is free to go—but she must stay. Guessing at the bargain she has struck with di Luna, the outraged Manrico delays, and Leonora dies in his arms. Count di Luna immediately orders Manrico’s execution and forces Azucena to watch. She tells him he has killed his own brother. Azucena’s mother is finally avenged.