Aurora High School looked as if someone had cast it from stone and sleep. The old, dark green walls hid more than even the oldest teachers would like to admit. At night, the building seemed even larger, and the windows carved long ago resembled the eyes of a watchful dragon. It was here, in the school library, that Lena, Adam and Igor met after lessons to complete their history project. Instead of focusing on the partition of Poland, they talked about something completely different. - Did you see that door behind the bookcase with ancient Polish literature? - Lena began, lowering her voice. - They look like they're from another era. Adam shrugged his shoulders, but Igor glanced at her curiously. - 'Are those the ones with the faded sign on the handle? - Yes! - Lena immediately became animated. - My grandmother used to tell me that there are nooks and crannies in this school that no one remembers. Within a few minutes, all three were already standing at the aforementioned door. The handle was covered with a greenish patina, and they recognised barely visible marks on the board. Lena pressed the handle. The door squeaked and opened abruptly, revealing a staircase leading downwards. They ran down them with beating hearts. The cellar was piercingly cold even on a summer's day, the air smelled of dust and something disturbingly fresh. A little light came through the ajar door and illuminated a section of the floor. Lena, leading with the torch on her phone, stopped suddenly. The outline of a circle drawn in chalk appeared on the ground, and around it, lines arranged in a web of corridors. Adam looked at Igor and Lena. He pulled out his phone to take a picture, but the screen only flickered. - 'I've got no reception... Suddenly they heard a clatter, somewhere in one of the dark tunnels. Lena moved ahead without a word and the boys followed her. Inside the tunnel, the light stopped on a strange metal box attached to the wall. They approached and Lena lifted the lid. Inside was a small, rusty lever, and next to it was an old poster with the words: 'Never go back alone. At the same moment, a quiet whisper came from the depths of the tunnel and something moved in the darkness beside them. Lena hesitated and Igor reflexively grabbed her arm. Ahead of them, the corridor branched into two equally black branches. Light began to come from one of them, and from the other... distinct footsteps. They stared at each other in silence for a moment longer, hesitating which way to go, when suddenly....