An animated film that tells the story of a shepherd who, while tending his sheep on the banks of a lake, sees a swan turn into a beautiful maiden. As a token of his love he throws her a leafy twig. whereupon she changes back into a swan and flies away. With the help of his mother, the shepherd follows her and eventually finds himself in the castle of a witch who has the power to change people into animals, a fate which will befall him if he fails to identify his love. Happily he recognises her by the twig he had thrown her and, with the witch's spell broken, she and all the other animals resume their human forms.