The school corridor in the old part of the building was usually empty and quiet, especially after lessons. Ola and Michael were just returning from an extra maths class, talking about the upcoming summer holidays. Ola, intrigued by the unusual noise, stopped in front of the door to the sports equipment storage room. A soft, metallic sound came from the closed room. - Did you hear that? - Ola asked in a whisper, surreptitiously glancing at Michal. The boy nodded, coming closer. The door was ajar. There was a strange, bluish light emanating from inside, which certainly could not have been given by any of the fluorescent lights. Ola took out her phone, switched on the torch and pushed the door wider. Inside stood old mattresses, a few broken balls and rows of cupboards. However, another sight caught their attention. On the back wall, just above the floor, there was a crack the width of a palm. It seemed that light pulsed from inside the crack and the air vibrated around it, as if it were heated. - What is this? - Michael rubbed his eyes. - After all, it wasn't here until yesterday. Ola crouched by the wall. She brought her hand close to the crack, but immediately withdrew it abruptly - her fingers were pierced by a brief tingling sensation, as if she had touched something electrical. Another sound came from the crack - a quiet whisper, whose words were incomprehensible but clearly spoke their names. They both held their breath, looking at each other with disbelief and a thrill of excitement. - 'We need to see what's on the other side,' Ola said, her voice trembling with emotion, not fear. At the same moment, the light became more intense. The edges of the crack opened wider, and a shadow resembling a hand flashed through the gap. The air rippled, and a distorted voice rang in Michael and Ola's ears: - You are the only ones who can pass... They took an uncertain step forward, their hearts beating faster. Just before the crack in the wall, surrounded by an unearthly light, they suddenly felt everything begin to change around them....