It was just after nine o'clock when Lena, Igor and Victor slipped out the side entrance to the City Library. They all claimed that the place takes on a completely different character after dark - some even spoke of ghosts, others of secret passages and old books that can whisper. For them, however, the library was first and foremost the perfect place to meet, free from parental eyes and boredom at home. That evening they waited for the librarian, Mrs Teresa, who - as every week - finished her work at the same time and always left the exit open for a few minutes before she locked the main door. They seized the opportunity and, with beating hearts, headed for the history books section. It was there that Lena found a strange, dusty book tucked deep behind the others, its title almost invisible: 'Untold Stories of the City'. - 'I've never heard of it,' Lena whispered, wiping the cover with her sleeve. Igor moved closer and ran his finger over the thick binding. The book began to tremble slightly, and a faint inscription appeared on its spine: "For the brave only". Victor looked at his friends with a mixture of excitement and anxiety. - 'Maybe... let's not open it here? - he suggested, but his voice died as Lena was already lifting the lid. Then there was a drawn-out, voiceless whisper - as if the whole library had taken in air and let it out at once. The lights dimmed, and somewhere between the bookcases something moved. On the pages of the book, which itself had begun to turn the pages, there was an illustration showing the familiar reading room - but with one detail: behind the bookcase they had just stood on, there was a hidden door they had never seen before. - I think this is... the plan of our library? - asked Igor, glancing uncertainly at the illustration. At that moment there was a quiet clatter at the end of the corridor, as if someone was approaching them slowly, very carefully. Lena closed the book, but something - or someone - was already very close. The three friends froze in stillness, trying not to breathe louder than the whisper of the paper pages. Behind the bookcase, where there should have been only a wall, a soft light appeared....