It was Christmas Eve, and snow was falling quietly outside the window. Zosia was helping her dad hang baubles on the Christmas tree. Mum was stirring borscht, and the cat was keeping watch over the dumplings. The living room smelled of oranges and cinnamon. Suddenly, Zosia noticed something behind the lowest branch. A small wooden ladder hung between the lights. It led to a round door, about the size of a plate. The door had a tiny bell and a shiny button. “Mum, can you see the little door?” whispered Zosia. Mum glanced over, but just then the kettle whistled in the kitchen. “I’ll be back in a minute, darling,” she called as she hurried away. Felek the cat jumped under the Christmas tree and began to purr. The bell gave a soft buzz, as if someone had brushed against it. Zosia knelt down and touched the button with one finger. The door trembled, and a warm light flickered on. “Hello? Is someone there?” she asked very quietly. From behind the door came the sound of tiny footsteps and whispering voices. Felek pricked up his ears, and the Christmas lights blinked twice. The button glowed red, and something rattled inside. Then, slowly — centimetre by centimetre — the little door began to open.