Three of ordinary schoolchildren – Jerry, Jimmy, and Cathy had summer vacation. After tiring lessons children had finally obtained freedom and escaped to the countryside in searching of adventures. Soon they found a hidden cave behind the bushes. Children's interest and adventurism makes them go down to the hole. When they passed that they have found themselves in a strange place. Later they have found a huge castle, and opposite it there was stretching a maze of hedges. After they had found the centre of a maze, they met a girl. Schoolchildren took this girl for an enchanted princess, as well as the castle became enchanted for them. The princess invites them to the castle and begins to show the wonders inside it. They find a magic ring, but will it give them only good?