Zosia is seven years old and has a red backpack. She is walking home from school through a small park. In the middle grows a huge, crooked oak tree. Today the tree purrs quietly, like an old windmill. Zosia stops and listens very carefully. She sees a tiny door with a leaf on the bark. The handle is cool, like the morning on the grass. Under the handle a circle glows, like a chestnut. Zosia applies her green button from her backpack. The wheel flashes and the door swings open. Behind them, soft light and mist flicker. The smell of apples and rain wafts from inside. Quiet bells and laughter can be heard, like an echo. Purr, Zosia's cat, is wagging his tail high. - Who is there? - asks Zosia very quietly. The light moves and whispers her name. The door slides open wider and something moves a twig. Something glints, like a golden scales, just inside the threshold. Zosia reaches out her hand and takes a step forward....