In a certain small house at the end of the street lived a girl called Pola. Her favourite place was a colourful room full of toys and books. One rainy afternoon Pola was tidying up her chest of drawers. Suddenly she noticed that one of the bottom drawers was slightly ajar. This was strange, because it had always been locked. Pola knelt down and gently pulled the tiny knob. The drawer opened with a quiet creak. Inside lay a blue key and a small paper scroll with a gold ribbon. Next to them was a card with a map of the room drawn on it. Poli's heart began to beat faster. What is this key? Where does the map lead to? The girl looked around the room and noticed something even stranger: a shadow appeared on the carpet in the shape of a door, which had not been here before.... Pola took a deep breath and decided to investigate the mystery. But what was behind this invisible door?