Basia and Kuba loved to visit their grandmother, who lived in an old wooden house at the edge of the forest. One evening, when the sky turned dark blue and the wind rustled quietly among the branches, Grandma put the children to bed in the lavender-scented attic bedroom. - 'Good night,' the grandmother whispered, turning off the lamp. The room was dark, but the silver light of the moon shone in from outside the window for a moment. Kuba was almost asleep when suddenly Basia whispered: - Kuba, do you see it? Kuba opened his eyes. A tiny light was flickering on the wall, just above the cupboard. There was no lamp there, no candle burning. - Maybe it's a skylight? - Kuba asked, although he didn't believe it himself. The light was too bright and moved slowly on the wall, as if it was looking for something. Basia slipped out from under the duvet and quietly slid her bare feet to the floor. - 'Come on, let's see up close,' she whispered to her brother. Cuba sighed, but curiosity was stronger than sleep. They both quietly got out of bed and started creeping towards the wall. At one point, the light stopped at a tiny door hidden just off the floor. - There has never been a door here! - Basia was surprised. Then the light flashed even brighter and... the door slowly started to swing open. A quiet creaking and a strange, barely audible giggling came from inside. Basia looked at Kuba with wide-open eyes, and Kuba felt his heart beating faster. Should they look inside? What hid behind the door from which the mysterious giggling was coming? Basia and Kuba took a few steps closer and then....