Basia was six years old and really enjoyed jumping on the large, colourful carpet in her room. Most often, she jumped together with her younger brother, Frank. One Saturday morning, when the sun was shining merrily through the window and the room smelled of strawberry oatmeal, Basia noticed something strange. A small, shiny circle appeared in the middle of the carpet. When she touched it with her finger, the circle shimmered and.... widened! The carpet slowly lifted at the edges, revealing a swirling, colourful light underneath. - Frank! Come quickly! - cried an excited Basia. Franek ran into the room and was surprised to see a strange portal under the carpet. - It looks like a tunnel! - he said in a whisper. Laughter and music could be heard through the portal. A green branch was sticking out of a brown hole and golden sparks were falling inside. Basia sat down carefully on the edge of the carpet. - I wonder where this portal leads... Maybe to a world where everything is made of blocks? Or to a land of talking animals? Franek reached out and touched the golden sparkles. - I think someone is calling us there! - ' he said, hearing a soft voice: "Come on in! Here is an adventure waiting for you!" The children looked at each other. Would they dare to enter the portal under the carpet, not knowing what they would find on the other side? Just when Basia was about to slip her foot into the coloured light, suddenly something began to approach from the depths of the tunnel....