King René’s daughter Iolanta is blind. But the girl is blissfully ignorant of her blindness: at René’s command, the mention of vision and light are forbidden in her presence. Iolanta’s father, friends and her old nurse are all polite and kind to her. The King cannot relinquish the idea of a cure for his daughter, but he is in disarray at the knowledge that in order for this to occur, Iolanta must learn of her blindness and wish to see. The knights Gottfried Vaudemont and his friend Robert appear at Iolanta’s tranquil shelter. Robert cares little for Iolanta, to whom he has been engaged from childhood, while Vaudemont falls completely and utterly in love with the girl. Left alone with Iolanta, Vaudemont asks for a red rose by which to remember her. The girl hands him a white rose and then Vaudemont, guessing at her blindness, tells her what she has been deprived of without sight, and speaks of the beauty of the world and of light. But Vaudemont’s words do not arouse a desire to see in Iolanta. In despair, King René threatens Vaudemont with death if his daughter cannot be cured. Fearful for the life of a man who has become dear to her, Iolanta agrees to an operation that will restore her sight. In the meantime, Robert admits to the King that he loves another and so he cannot marry his daughter. On finding out that Iolanta can see, the King forgives Robert, frees him from the vow he has taken and gives his approval of his daughter’s marriage to Vaudemont. At the wedding, all the guests sing a thankful hymn in God’s praise. The festivities die down, and Iolanta is left alone.