The old brick library at School Complex Number 5 has long aroused the curiosity of pupils. It was said that during thunderstorms they could hear rustling in it and that a shadow was seen on one of the bookcases. Most considered these stories to be concoctions, but for Nicholas, Ola and Igor, they became the start of something more. One Friday evening, when all the lights had gone out and the school corridor had quietened down after the final bell, the three friends slipped out of the gymnasium. In their hands they held torches and a phone with an audio recorder. The challenge was: to spend half an hour in the library, about which legends circulated. They reached the door. It opened with a quiet creak, and from behind the bookcases they could feel the cold and the slight smell of dust. Igor was most interested in the old library catalogue. Ola shone her torchlight on the cobweb-covered wall. Nikolai stopped at a hollow spot in the floor. Peering through the dusty window, they saw a shadow run past the wall. - 'Did you hear that? - whispered Igor, sliding closer to his friends. A whisper came from the depths of the room, quiet, barely perceptible, resembling the echo of muffled, unintelligible words. The torches began to flicker. At that moment, Ola noticed that a section of brick had come loose at the end of a bookcase, behind a large wardrobe. The friends came closer, pressing one against the other. Nikolai gently pushed the brick away, and to their eyes appeared a narrow corridor leading deep into the wall. Suddenly, a sound like a creaking door and a long, unnatural rustling sound came from behind them. They froze in place, and the whispering grew into clearer, though still unintelligible words....