 Alfonso, who has seduced Fenella, the Neapolitan Masaniello's mute sister and abandoned her, is tormented by doubts and remorse, fearing that she has committed suicide.During the festival Fenella rushes in to seek protection from the Viceroy, who has kept her a prisoner for the past month.She has escaped from her prison and narrates the story of her seduction by gestures, showing a scarf which her lover gave her.