At a lakeside clearing in the moonlight, Prince Siegfried is transfixed by the appearance of a swan which changes before his eyes into the Princess Odette.

She and her maidens are victims of a terrible spell cast by the evil, owl-like sorceror Von Rothbart. By day they are turned into swans and only at night, by the side of the enchanted lake, do they return to human form.

The spell can only be broken if one who has never loved before swears to love Odette forever.