Alcina, a powerful sorceress dwelling on a remote island, enchants all who arrive at her shores, transforming them into animals, rocks, or trees to maintain her dominion. When the knight Ruggiero lands with his companion Bradamante—who disguises herself as a man named Ricciardo—Alcina becomes infatuated with the handsome warrior. She uses her magic to keep him captive, promising eternal youth and pleasure. Bradamante, tormented by jealousy and the necessity of her disguise, struggles to reveal her true identity and reclaim her beloved. As the sorceress's power grows more desperate and possessive, her sister Morgana and the knight Oronte become entangled in the web of enchantment. The opera explores themes of illusion versus reality, the destructive nature of obsessive love, and the triumph of virtue over magical deception. Through a series of magical transformations and revelations, the spell is ultimately broken, freeing Ruggiero from Alcina's grasp and allowing true love to prevail.