The Tale of Tsar Saltan (1966 film)

Three sisters are sitting by the window telling each other what they would do if the Tsar marries them. The first one would arrange a wedding banquet for all people, the second would dress everyone elegantly. The third and the youngest, however, says: "I would not give the Tsar money and goods, but instead a son with strength and courage."

The Tsar, who hears this conversation, takes the youngest woman as his wife. He places the other two as court cook and weaver. Envious of their youngest sister, the two join and come to the Tsar's court.

Some time later, the Tsar must go to war. His wife tells him in a letter that she has given birth to a son. The Tsar's reply is intercepted by the sisters and the mother-in-law and falsified to be so that the wife and son are sealed in a keg and thrown into the sea.

After a while they find themselves on a beach of a barren island. There the adult son rescues the life of a swan. This swan is a swan maiden, an enchanted princess. She creates a beautiful city for the mother and son, whose inhabitants make him Prince Gwidon. The swan also helps Gwidon disguise as an insect to see his father.

Some time later, the Tsar – against the wish of the sisters – comes to this city and recognizes his wife and son again.