Ola really enjoyed walking in the forest with her dog Dropsik. One afternoon, when the sun was shining through the leaves and flowers were smelling everywhere, Ola noticed something strange under an old, spreading oak tree. There was a small golden door sticking out between the roots of the tree! Dropsik barked and sniffed the handle. - Dropsik, have you ever seen this? - Ola asked. The door was no bigger than her backpack. Ola crouched down and looked at them carefully. There was a small blue key hanging on the handle. The girl took a deep breath, looked at Dropsik and together they decided to open the door. As soon as she turned the key, a mysterious coloured light flashed behind the door! Quiet laughter and the sound of bells could be heard. Ola opened the door wide and Dropsik was the first to slip his nose inside. Beyond the threshold, something unusual was waiting for them....