Act I

The enchantress Alcina attracts men to her magic island where they are transformed into rocks, streams, trees and wild beasts. But for the first time she has fallen in love. Her new lover is called Ruggiero. Bradamante, Ruggiero’s fiancée, has disguised herself as her own brother Ricciardo in order to find her lost lover. She is travelling with Ruggiero’s former tutor, Melisso. They arrive at Alcina’s palace where they are met by Morgana, Alcina’s attendant, who immediately falls in love with “Ricciardo”. Alcina appears with Ruggiero, who is totally captivated by her and has lost all memory of Bradamante. Also on the island is Oberto, a young boy searching for his father. Hoping to dispose of his rival, Oronte maliciously tells Ruggiero that Alcina is herself in love with “Ricciardo”. Alcina denies this accusation but decides to transform “Ricciardo” in order to prove her love to Ruggiero. Morgana warns “Ricciardo” of this plan before openly declaring her love for him.

Act II

Melisso breaks Alcina’s spell over Ruggiero. As a result, Ruggiero remembers his love for Bradamante, but following Melisso’s instructions, pretends still to love Alcina. The enchantress is about to transform “Ricciardo”, but Morgana succeeds in protecting “him”. Oronte reveals to Alcina that Ruggiero has betrayed her and is planning to escape. Alcina is heartbroken. Ruggiero, reunited with Bradamante, bids farewell to the illusory beauty of Alcina’s magic world. In vain the Enchantress attempts to prevent the departure of Ruggiero. She despairs at the loss of her powers.

Act III

Morgana, having discovered the true identity of “Ricciardo”, attempts to win back Oronte, but he pretends indifference. Alcina confronts Ruggiero: she vows vengeance, but will forgive him if he returns to her. Together with Melisso and Bradamante, Ruggiero makes plans for their escape. Bradamante reflects on the reward of fidelity. Alcina longs to be delivered from her suffering. As Bradamante and Ruggiero are about to leave, Alcina begs her lover one last time to remain with her. He refuses. Alcina’s magic is destroyed and the transformed men are returned to their former selves…