With the aid of magical powers, the mighty sorceress Alcina has transformed a desert island into an Elysium, while on the European mainland Charlemagne is busy recruiting every noble hero for the battle against the Moors in Spain. Time and again Alcina lures knights away from the campaign onto her island. She bestows the joys of love upon the chosen ones, until she tires of them and turns them into animals, plants and even rocks. Numerous knights of Charlemagne’s army are already missing. The young Oberto is searching for his father Astolfo and has at least already made it as far as Alcina. However, he cannot find his father: no wonder, since the latter is wasting away in the island menagerie in the form of a lion. Alcina’s current choice of lover is the famed Ruggiero. He is utterly in thrall to her. However, his betrothed, the female knight Bradamante, and her tutor Melisso who is also capable of sorcery, have set off in search of the missing hero. Eventually they land on Alcina’s island. Bradamante is disguised as a man and calls herself “Ricciardo”. But this disguise soon has her caught up in amorous entanglements: Morgana, Alcina’s sister, falls in love with “Ricciardo”, deserting her previous lover Oronte. Bradamante plays along with this unintended deception, hoping it will help her gain access to Ruggiero. Oronte, deeply hurt, tries to get rid of the visitors and uses every means in his power to plot against them. Despite all his efforts, Bradamante’s plan succeeds: with the aid of Melisso’s counteractive spell, Ruggiero finally sees the reality behind Alcina’s magical landscape and frees himself from her influence. The three of them have to be cautious when preparing their flight because Alcina notices that Ruggiero is slipping from her grasp. But because she genuinely loves him, her powers die along with his love of her. The spirits of the underworld refuse her their allegiance. When Ruggiero leaves the island he destroys Alcina’s magical powers. All her previous victims regain their original forms, the island is revealed as a wasteland, and Alcina becomes a lonely old woman bereft of any magical splendour. The knights go back to war. A victory of love?