Once upon a time, just outside a big, thick forest, there lived a boy called Janek and his little sister Jagna. They had a thatched hut, and behind the house grew huge oak trees and old, humming pine trees. One sunny morning Janek said: - Come on, Jagna! We'll go into the forest to look for forest strawberries! Jagna smiled broadly, grabbed the basket and together they ran along a path that led straight into the green shadows of the trees. As they walked deeper and deeper, they could hear birds singing, the whispering of leaves and the sound of squirrels leaping through the branches. The forest was huge and very, very old. Suddenly, from behind a large stone, a pretty, silvery squirrel leaned out. It had fur that glistened like snow in the sunlight. The squirrel looked at the children and honked: - Follow me! - and immediately ran through the ferns. Janek and Jagna looked at each other surprised, but curiosity was stronger. They followed the squirrel, passing old trees and moss-covered roots. At one point, they saw something unusual - among the bushes was a tiny door, decorated with carvings in the shape of leaves and flowers! - Is this a house for forest gnomes? - whispered Jagna with her eyes wide open. - I think so... But should we knock? - wondered Janek, looking at the door. Just then a quiet knock-knock-knock came from behind the door....