The night air was saturated with the smell of dampness after the afternoon rain. As Zosia, Michal and Lena stood under the high fence of the former primary school No. 7, the world seemed strangely quiet. By the glare of the streetlights, their shadows lengthened among the broken paving slabs. The school had stood closed for years - it was rumoured that the ceiling in the gymnasium had once collapsed here and no one had renovated it since. Rumours circulated around the neighbourhood, but none of the adults wanted to talk about it. When Michal found a hole in the fence to squeeze through, Zosia felt her heart speed up. She had the feeling that someone was watching them from the dark windows of the building, although reason tried to convince her that it was just her imagination. - Do you remember what Kuba said? - Lena whispered, hiding behind a stone pillar. - That someone had heard someone's laughter in the old cloakroom.... - 'Pff, he certainly made it up to scare us,' Michal muttered, although he was squeezing the torch tighter than usual. They tore through the grid, leaving the familiar street behind. The dark blue facade of the school, stripped of its plaster, gave the impression that the building was about to fall apart. They moved up the creaking stairs, taking a video on their phone - as proof to the rest of the class that they were not cowards. Inside, the air was cool. The echo of their breaths echoed off the walls, and the pale torchlight revealed remnants of the old days: blackboards covered with dusty chalk drawings, old posters and school bags abandoned in the cloakroom. - I can see the door to the basement," whispered Michael. Behind them stretched a steep staircase downwards. Lena and Zosia exchanged glances. Everything in them cried out to turn back... but curiosity won out. They descended slowly, hearing each of their steps. A long, dark corridor awaited them at the bottom. At the end, a faint green light was burning - the only thing that didn't belong in an abandoned building. - 'There's no way this is just imagination,' Lena whispered. Then, right next to them, something rustled. Michael's torch shuddered, and a shadow appeared on the wall that definitely didn't belong to either of them....