Outside the window the rain was falling and tapping on the windows. The school library smelled of paper and old wood. Zosia liked to help Mrs Hela here after lessons. She arranged the books and counted the colourful bookmarks. Suddenly, she heard a quiet whisper between the bookcases. Zosia looked at the window; it was tightly closed. - Is someone calling me? - Zosia whispered. A dark blue envelope without a stamp was lying on the shelf. There was an inscription on the envelope: For he who is listening. Inside was a map with stars and arrows. She had made an appointment with Maks, her best friend. Maks came in quietly and took off his backpack. The map told her to count the steps from the big clock. Maks whispered the numbers while Zosia held the map. They passed the globe, the bear rug and the Fairy shelf. The whisper sounded again, like a leaf by the ear. - 'Take the light and you will find the key,' whispered the voice. Then above the table the lamp tinkled and something flashed. Behind the bookcase a curtain moved, as if someone was breathing. Zosia looked into the gap with Max and saw....