ACT I. The guard room in the castle of Luna. Ferrando, an old and trusted vassal of the count, orders the guards to keep watch while Di Luna wanders restlessly beneath the windows of Leonora, whom he loves. Luna's heart is torn with jealousy against his fortunate rival, the troubador Manrico. In order to keep awake, Ferrando narrates the history of the count to the guard. (Fernando: "Once upon a time a father of two sons lived happily.") It appears that a gypsy of dreadful aspect had once exercised her magic arts upon the little brother of the count, making the child weak and ill, and for this had been burnt alive as a witch. Dying, she had commanded her daughter Azucena to avenge her, which vengeance had been partially accomplished by the carrying off of the child. Although no news had been heard of him, the father refused to believe in his son's death, and dying, commanded his son, Count di Luna, to seek for the gypsy. Change of scene: Garden in the palace of the princess. Leonora confesses her love for Mannico to her confidante, Inez. ("The stars shone.") When they have gone, Count Luna hears the voice of his rival. (Manrico, behind the scenes: "Alone and forsaken am I.") Leonora in the darkness mistakes the count for her lover, when Manrico himself enters the garden, and she rushes to his arms. The count recognises Manrico as his enemy, who has been condemned to death, and endeavours to compel him to fight. When they cross swords Leonora intervenes.
ACT II. Camp of the gypsies. Manrico at the bedside of his mother, Azucena. (Chorus: "See the clouds in heaven's vault.") Azucena is the daughter of the gipsy burnt by the count. She is old, but still nurses her vengeance. (Aria: "Flames rise to heaven.") The gypsies break up camp while Azucena confesses to Manrico that after stealing him she had intended to burn the count?s little son, but had thrown her own child into the flames instead. Manrico realises that he is not the son of Azucena, but loves her as if she were indeed his mother, as she has always been faithful and loving to him. A messenger arrives and reports that Leonora, who believes Manrico dead, is about to take the veil. Manrico rushes away to prevent her from following out this purpose. Change of scene: Before the convent. Luna and his attendants intend to abduct Leonora. (Aria: "Her eyes' heavenly light.") Leonora and the nuns appear in pro-cession, but Manrico prevents Luna from carrying out his plans.
ACT III. Luna's camp. (Chorus: "In the midst of conflict.") Ferrando brings in the captured Azucena. She is recognised by Luna and sentenced to be burnt. Change of scene: Chamber in the castle, which is besieged by Manrico. Leonora and Manrico live only for each other. (Aria, Manrico: "For you, my dear one, would I willingly die.") Ruiz, Manrico's comrade, reports that Azucena is to be executed. Manrico flies to her aid. (Stretta: "I see the flames to heaven reach.")
ACT IV. Before the dungeon keep. Leonora attempts to free Manrico, who has been captured by Luna. (Miserere of the prisoners and aria of Manrico in the turret: "The death hour is near.") Leonora begs Luna for mercy and offers herself in place of her lover. She promises to give herself to the count, but intends to take poison before the marriage. Change of scene: Manrico and Azucena. Manrico attempts to soothe Azucena, whose mind wanders. (Duet: "Home to our mountains.") At last the gipsy slumbers. Leonora comes to Manrico and tells him that he is saved. When he discovers she cannot accompany him, he refuses to leave his prison. He believes Leonora to be a traitress until he hears that she has taken poison to remain true to him. As she dies in agony the count enters and orders Manrico to be led to execution. Azucena arises from her couch and when Luna, dragging her to a window, shows her the dying Manrico, she cries in triumph: "He was your brother. Now are you avenged, mother!" and falls dead at his feet.