The Black Hen, or Living Underground (1980)

At a St. Petersburg boarding school, a new life began for the ten-year-old Alyosha, who was accustomed parental attention. Missing his home, Alyosha created an imaginary magic world of underground dwellers, with a king and his subjects who very much resembled the people surrounding the boy. Alyosha experienced many interesting adventures in this mysterious fairy tale. However, he failed to keep the cherished secret of its existence in the real life. And the underground dwellers left him for good…