Ola and Franek loved playing in their grandmother's garden. One day they noticed something strange - there was a small tree house hidden behind an old currant bush that no one had visited for a long time. The steps creaked as they climbed up. Inside lay an old, colourful carpet and lots of books with pictures of monsters, dragons and mysterious lands. Suddenly, as Ola opened one of the books, she felt as if the air became very light and the colours around her became more intense. Frank looked out of the window and saw that the garden now looked completely different - the flowers were dancing and the butterflies had golden wings. A shiny key appeared in the corner of the cottage and quiet laughter began to reach them. - Can you hear it? - whispered Ola. Frank nodded and looked at the key, which lay on the carpet and slowly began to glow brighter and brighter....