Zosia and Kuba loved spending their holidays with their grandfather in the countryside. Every day they invented new games, but this time they decided to explore the cellar, which apparently no one had entered for years. Grandpa only smiled mysteriously when they asked him about the locked door under the stairs. One cloudy evening, when a storm was raging outside the windows, the siblings gathered their courage. Zosia found an old key attached to a bundle of old keys in a kitchen drawer. It was made of metal that glittered like gold. The door to the cellar creaked open and the staircase led deep into the ground, where it smelled of dust and lavender that her grandfather had stored in drying racks. Cuba shone his torch and Zosia held the key tightly in her hand. At the end of the cellar stood a wooden chest of drawers. Its bottom drawer looked different from the rest - it was decorated with carved dragons and mysterious signs. As Zosia slid the key into the lock, she suddenly felt warmth in her fingers. The chest of drawers began to tremble, and a light came out of it, as if there was a lantern inside. Zosia and Kuba looked at each other in disbelief. The light created a swirling mist that began to suck in the air around them. In an instant they heard strange voices and shadows flashed before them. "Maybe we should go back?" - whispered Kuba, but Zosia was already extending her hand towards the portal. And then, completely unexpectedly, a paw with glittering scales emerged from inside the dresser and a mysterious voice asked: "Who dares to cross the border of the Underground Kingdom?"