Mystery of the Green Mirror

The cellar at her grandmother's house has always been a place full of puzzles for Nina. She tended to stay away from the dusty cardboard boxes and cobwebs, but on this holiday afternoon, she and her younger brother Kuba decided to climb down the stairs and see what was hiding in the darkest corner. Behind a pile of old books, they found something unusual - a large green mirror in a heavy gilded frame. Kuba's eyes immediately lit up. "Wow, look how strange!" - he whispered. The mirror seemed to absorb the light and... vibrate, like a sheet of water. Nina wiped the glass with the sleeve of her jumper and suddenly saw her own face fading in the reflection, replaced by swirling coloured mists and blurred silhouettes. Cuba touched the glass and... his hand disappeared on the other side! "I don't believe it!" - squealed Nina. Before she could stop him, the boy pulled his sister behind him. For a second, everything around them shimmered green, and then the siblings suddenly stood in the middle of a forest where the leaves glowed blue and the trees whispered something quietly. A strange creature appeared in the distance, a bit like a fox, but with a plume on its head. It looked at them with yellow eyes and.... Nina and Kuba felt something gently grab their shoulders. Were they supposed to go home? Or move after the magical creature? Luminous dots began to appear in the forest, and somewhere nearby the crackle of branches sounded....