Swan Lake is a bittersweet tale recounting the love of Prince Siegfried for Odette, who, as the result of the evil sorcery of the magician von Rothbart, is transformed into a swan by day, though she is allowed to return to her human form by night. Only absolute fidelity in love can destroy the spell. Von Rothbart is determined that Siegfried will break his oath to Odette by falling in love with the seductive Odile, von Rothbart's own daughter.