Oliwia, Janek, Basia and Igor have always been looking for adventure. This time they chose as their destination a place that was talked about in whispers all over the estate - an old mill by the river, just beyond the dark line of the forest. The building was overgrown with ivy and had broken windows. Everyone knew it was better not to go there after dark. But for Olive's pack, there were no prohibitions that could not be broken. - I bet none of you will last more than an hour in there! - cried Igor, waving his torch. Basia just rolled her eyes. - 'Sure, I can already see you're scared of the cobwebs, Igi,' she replied with a smile, but squeezed Olive's hand slightly. She was shivering, although it wasn't cold at all. They decided to climb in through the ground floor window. Janek pushed himself in first, as he was the lowest. He was followed by the rest, carefully so as not to cut themselves on the protruding pieces of glass. As soon as they were inside, the light from the torches danced across the walls, casting strange shadows. Something seemed to creak under the floor.... The mill was even bigger than they had expected. Sheaves of moonlight came through the gaps in the boards, drawing patterns on the floor. The smell of wet wood and dust was everywhere. Basia immediately spotted a staircase leading upstairs. - Let's go up there! - she whispered excitedly, pointing her finger. Climbing up the steep, creaking steps, they felt their hearts beating faster. It was darker upstairs and the air was even heavier. Moving away from the entrance, they suddenly heard someone's footsteps... or maybe just the echo of their own breaths? Suddenly Olive noticed something shiny under the old table. She trembled when she saw a rusty key on a leather thong. At the same moment, a quiet knock sounded behind the large door on the other side of the room. The friends looked at each other with wide-open eyes as a draughty, cold gust pierced the air.... The door squeaked and began to slowly open.