No one should be here after dark. The abandoned high school, standing on the worn-out edge of the neighbourhood, evoked a chill even during the day. But for Olga, Simon and Lena, there was no more interesting place to test their nerves - and courage. It all started with that one rumour they had heard at the break: apparently someone had seen a light in one of the former chemist's offices. When Simon looked at his friends with a spark of challenge in his eyes, they knew that no one would leave the situation without testing it out for themselves. The evening was sultry and full of June sounds - crickets buzzed almost as loudly as the hearts of the three friends as they slid through the hole in the net. The corridors of the old school resembled a maze, with each step causing an echoing clatter. Lena, usually the bravest, was now walking last, clutching an old camera in her hand. Olga led the way, carefully sweeping each dusty nook and cranny with her torch. Simon kept repeating jokes, trying to relieve the growing tension, but his voice betrayed the nerves he was trying to hide. Finally they reached the chemical laboratory. Everything looked as if time had stopped here - bottles with label remnants, broken vials and empty cabinets. It was so quiet that they could hear their own breathing. Suddenly, Lena stopped as if she had been stumped. - Look at this... - she whispered, pointing to the back wall of the room. A narrow gap appeared between the plaster tiles running along the wall, which had not been there before. A pale light seeped from within it, and a moment later they heard muffled sounds - something like rustling, mixed with quiet laughter. Olga felt her heart speed up. Lena squeezed the camera even tighter. Simon, though pale, took a step forward, trying to look inside. Suddenly, a clear whisper came from behind the gap, as if someone was saying something on the other side of the wall. Everyone froze, not knowing what to do next - and just then something on that side began to move, rasping quietly. All three stared at each other with wide-open eyes, feeling a growing fear and excitement. Their emotions were mixing, simmering just below the surface. What were they to do next? Would they dare to get closer, or run away before something or someone appeared in the crevice?