The medieval Irish princess Isolde wants to poison the knight Tristan for wrongs he has done her, but falls in love with him instead when her maid, Brangäne, substitutes a love potion for the poison. Some time later Melot, another of Isolde s suitors, grievously wounds Tristan. Tristan returns to his home in Brittany, tended by his faithful knight Kurwenal. Isolde arrives, hoping to cure Tristan with her magic herbs, but is too late. Holding Tristan in her arms, she sings a soaring hymn to the bliss of eternal passion.