Alcina, a powerful sorceress dwelling on a remote island, enchants all who arrive at her shores, transforming them into animals, rocks, or trees to preserve her youth and beauty. When the knight Ruggiero lands on her island, she falls desperately in love with him and uses her magic to keep him captive. Ruggiero's betrothed Bradamante, disguised as her brother Ricciardo, arrives seeking her lover, while Alcina's sister Morgana and the courtier Oronte become entangled in the web of desire and deception. As Bradamante works to break Alcina's spell and free Ruggiero from her enchantment, the sorceress's power begins to crumble. The opera culminates in a spectacular display of magic undone, as Alcina's island fortress collapses and her victims are restored to human form, revealing the ultimate triumph of true love over supernatural artifice.