Count Di Luna and Manrico are rivals for Lady Leonora's love. When Leonora declares her love for Manrico, the two men duel. Although Manrico has the chance to kill Di Luna, a mysterious force from within him stays his hand and allows Di Luna to live. Later, Manrico listens to his aging mother, the gypsy Azucena, describe the death of her own mother, who was burned at the stake after being accused of hexing a nobleman's son. Azucena vowed revenge, and tried to kill the nobleman's second-born son, but accidentally killed her own child instead. She raised the younger son as her own. That younger brother was Manrico. Azucena assures Manrico that although he is not her biological son, she still loves him as a mother.
Word comes that Leonora, thinking Manrico dead from the duel, will be entering a convent. Both Di Luna and Manrico try to intercept her on her way, leading to another fight, and the escape of Manrico and Leonora together. Di Luna and his men follow them and set up camp. A guard discovers Azucena hiding. As she describes her sorry life, Di Luna recognizes herthe gypsy who kidnapped and killed his brother, and the daughter of the gypsy who cursed him!