The film is based on a popular Russian folk tale.

There once lived a father who had three sons. His two elder sons, Anton and Agafon, had chosen themselves regular girls for brides, but the youngest one, Ivanushka, brought to his home a frog from the marshes. The father was very much surprised, but didn’t say anything. However, the frog was actually a beautiful girl, Vassilisa, over whom Gorynych the Serpent had cast a spell. Vassilisa refused to marry the monster and he turned her into a frog. But Ivanushka did not renounce his love. He had to overcome many obstacles before he returned to Vassilisa her former appearance and killed the three-headed dragon.