Synopsis: In the mountains of Vizcaya, a band of gypsies are gathered round a large fire. Azucena broods over the fire. She sings a ballad of a pitiful woman being dragged by a howling mob toward the flames. As the others depart, Manrico, who has been lying at her side, asks her to tell her the story that inspired such a sad song.
She tells him how her mother was accused by a haughty Count of having bewitched his young son; how she was brought in chains to meet her doom at this very spot; how she herself followed, her own baby in her arms, weeping; how her mother tried to stop and bless her, but was viciously thrust upon the stake. Her mother’s last words, in her death agony, were “Avenge me!” Those words have ever since echoed in her heart.
Manrico asks if she was avenged. Azucena replies that she abducted the Count’s son and brought him here, where the fire still burned. The baby cried piteously; her maternal feelings broke her heart; suddenly a horrible vision appeared: the killers; the torture; her mother crying out “Avenge me!” Blindly she siezed the victim in her trembling hand and thrust it on the fire. In an instant the vision was gone. Only the raging flames remained, consuming their prey; and there beside her was the son of the wicked Count. It was her own son she had cast into the fire! (from opera.stanford.edu)