The castle of Rene, the King of Provence is in the south of France. The King’s young daughter, Iolanta, lives here. She is blind from birth, but she doesn’t know it. By the King’s orders the terrible secret is carefully kept from her. No outsiders are allowed in the castle under the fear of death. Blissfully unaware, Iolanta lives a carefree and life among her friends. The King brings a famous Moorish physician to her. Worried, Rene awaits for his answer. The physician tells him that recovery is possible, but Iolanta must be made aware of her affliction. She must wish the recovery of her sight; only then will the cure work. But the King is steadfast.
Two knights, Robert and Vaudemont, happen to visit the garden: Robert has been betrothed to Iolanta since childhood; he has never seen her and is not aware of her blindness. Vaudemont goes up to the beautiful garden terrace and sees the sleeping Iolanta. Her maiden beauty enchants the young knight. His involuntary cry of admiration wakes the girl. The young knight’s excitement stirs Iolanta’s soul. The emerging feeling thrills and confuses her. While saying goodbye the marvelous stranger, Vaudemont asks for a red rose as a keepsake. Iolanta picks a white rose instead of a red one. The realization terrifies the knight. Feeling compassion for the girl, he describes the beauty of the light to her. Iolanta is enraptured by his words. The King appears. Learning that the stranger has revealed the secret of light to Iolanta, the King is furious, but the physician calms him. Now the cure is possible, she only needs an inner desire to see. Suspecting their love, the King feigningly threatens Vaudemont with the death sentence if Iolanta’s sight is not restored. Iolanta is ready to endure any pain to save her beloved. The treatment works. Astonished and delighted to be able to see the world, Iolanta recognizes her father, her friends, and Vaudemont, who henceforth will be her protector.