Basia and Kuba were best friends. One sunny day they decided to build their own tree house in Basia's garden. They brought a board, a hammer and lots of colourful cushions. When the house was ready, they went inside and started to set up their new play area. Unexpectedly, they saw something shiny under one of the leaves. It was a small golden key! The key had strange markings on it: a star, a moon and a cat. Basia said: - I wonder what this key might fit into? Kuba looked around carefully. In the corner of the cottage he found a tiny door that they had not seen before. The door was so small that they had to bend over to look inside. - Maybe this is the key to this door? - whispered Kuba. Basia smiled broadly. She carefully slid the key into the lock and turned it. The door began to open slowly and a soft blue light appeared behind it.... What would Basia and Kuba find on the other side of the magic door?