The Christmas market in Birchwood smelled of gingerbread, oranges and spruce. Maja, a fourteen-year-old from a neighbouring street, was helping her grandmother sell hearts with icing. Above the market, the big star on the Christmas tree shone and the town hall clock was silent. The silence had lasted for years, ever since the winter key to its mechanism had gone missing. People whispered that when it sounded again, it would bring an extraordinary Christmas Eve to the town. Maya laughed at the legends, but this winter something sounded like a tight string inside her. In an old wooden molding she found a thin, brass key in the shape of a snowflake. Beneath it lay a folded scrap of paper with cursive old calligraphy. - If you want to hear the time, come after dark to the north side - the inscription read. At the very bottom was the signature: the mysterious Carol of the North, as if from a fairy tale. - 'Someone's probably playing a joke,' muttered Bartek, who approached with his skates on his shoulder. Maja put the key in her pocket and felt her hand grow warmer. The evening had thickened, the snow was creaking and the lanterns were drawing golden spots on the ice. By the crib under the Christmas tree, Maja noticed a tiny keyhole, almost invisible. - 'The north side is here,' she whispered, pointing to the figure of the Three Kings standing to the north. The key slid in with a quiet click, and a secret flap in the wood swung open. Inside lay a map of the market with an arrow drawn on it and the inscription: Entrance: North. A barely audible beat came from below, as if someone was trying to start an old clock. She led Bartek past the stalls until they came to a cast-iron grate by the wall of the town hall. The snowflake key fitted perfectly; the grating gave way and a narrow stone staircase appeared. The music from the speakers died down and the air smelled of metal, cinnamon and something very old. They were walking down, counting the steps, when suddenly the lights in the marketplace twitched and the Christmas tree dimmed. - Can you smell it? - asked Bartek, as a soft, deep chorus came from inside. Downstairs, a door with a frosty snowflake symbol waited and lit itself. The clock struck thirteen, and someone on the other side whispered Mai and Bartek's names.