In the old edifice of the College of Technical Sciences, darkness reigned even during the day. Room 213, usually full of noisy students, this evening resounded only with the quiet rustling of papers and the clink of coffee cups. Patrick, Ola and Damian were bending over their notes, trying to assimilate the formulas and definitions that awaited them in tomorrow's exam. The wind was rumbling against the windows and the creaky old radiators added to the harshness of the setting. At one point, Ola broke the silence: - Can you hear it? - She asked, peering down the dark corridor. A quiet clatter sounded behind the door. Patrick shrugged his shoulders, but Damian turned pale: - 'It's not the first time today. Every time I look at my watch, it's the same time: 23:13. The decision was made quickly. With torches in their phones, they set off towards where the sounds were coming from. As they walked through the deserted corridors, they looked at cabinets covered in dust and old blackboards with twisted letters. When they reached the end of the wing, the murmuring had quietened. In front of them was the closed door to the chemistry lab that everyone had heard strange stories about. The handle was cold, as if no one had touched it in years, but to their surprise the the door suddenly gave way under slight pressure. The interior smelled musty and of the past. In the light of the telephones, they noticed wet footprints on the floor, leading deep into the room. Above them on a shelf stood rows of jars of strange substances, and at the end of the room, at a table covered with a black oilcloth, something moved.... The friends froze, holding their breath. Would anyone dare to come closer?