There was always something strange going on in the school boarding school, but it was only that evening that Lena, Adam and Maks felt that something more was at stake. The wind was rustling the curtains in room 312 when Lena accidentally dropped a book on the floor. A small, yellowed page fell out of its interior. The lines drawn on it formed something that resembled a plan of the boarding house - but with a few differences. - What is this? - Maks asked, leaning over the sheet of paper. He pointed to a section where a thin line led from the door of their room to a place signed: 'Non-drawer'. Adam swallowed his saliva. - After all, there isn't even a drawer here.... - he muttered, but he was already looking for the torch on his phone. They checked under beds, behind wardrobes, even under the carpet. The clock showed 22:13, and the voices from the corridor had quietened down. Finally, Lena noticed a tiny crevice under an old chest of drawers. There, almost invisible, was a shallow drawer that no one had ever opened. Her heart beat faster as she touched the handle. The drawer squeaked and opened slowly.... Inside, apart from the dust, lay a small silver key and another, even more puzzling map. This time it led to a place neither of them recognised. There was only one inscription on the back of it: "When the clock strikes thirteen, follow the pointer". Outside the window, the wind howled louder and louder. The friends exchanged glances - none of them thought of retreating. Just then they heard a quiet knock on the door of room 312....