The Old Town Library had been closed after dark for years, and its deserted corridors were known only to a few. Julka, Kuba and Basia, a pack of puzzle-loving friends, decided to have a night-time adventure right there. They walked quietly through the garden, jumping over a rusting gate. The key Kuba had found in his grandfather's drawer fitted the old lock perfectly. As the door creaked open, a flash of torchlight light illuminated the dusty shelves and the old portraits of authors looking stern from the heights of the walls. The clock struck midnight. The library seemed to suddenly come alive - somewhere between the shelves, quiet whispers could be heard, as if the pages of the books were turning by themselves. - Did you hear that? - whispered Basia, squeezing her friends' shoulders. - Maybe it was the wind? - Kuba tried to joke, but his voice trembled. Julka approached the bookcase with the oldest books slowly. Between 'Secrets of the Night' and 'Diary of Lost Hours', she saw something strange - a pressed letter on yellowed paper. She looked at her friends before opening it; they all held their breath. Suddenly, right next to her, there was a deafening clatter. Torchlight danced on the walls and a shadow flashed across the end of the corridor. As the friends moved slowly in that direction, they found an ajar door leading to a forgotten attic. There were mysterious whispers coming from inside, as if someone was reciting excerpts from old books. Julka clutched the letter in her hand and Kuba gently pushed the door open.... Curiosity overcame fear - they decided to enter the attic, not yet knowing what awaited them there.