At the Mroczek University, hidden between the grey tenements of the old town, time flowed a little differently. The old walls seemed to whisper stories from centuries ago, and dusty corridors led to places about which one could vainly find information in guidebooks. On one gloomy autumn evening, when most of the students were preparing for their colloquia, Anka, Michał and Lena decided to take a look in the cellar under the faculty library. On the surface, they were looking for Lena's lost bag, but in fact they were driven by simple curiosity. As they descended the narrow staircase, they were greeted by the smell of dampness and the quiet echo of footsteps. The torches from the phones only slightly illuminated the darkness. Old bookcases bowed under the weight of books, most of which still remembered the days when computers were fantasy. Suddenly, Anka stopped abruptly. - Have you seen this? - She whispered, pointing to a section of wall behind a globe standing alone. They moved the globe and a small metal door appeared to their eyes. Someone had painted a strange sign on them - something between the letter 'M' and a key. Without hesitation, Michal grabbed the handle. To his surprise, the door gave way with a quiet creak. Behind them, a staircase led down even deeper. It grew colder with each step, and echoed off the stone walls. At the end of the corridor, the light of some old-fashioned lamp shimmered. Suddenly they heard a rustle, as if someone's quiet footsteps were coming from behind another door. They stopped, holding their breath. A shadow appeared on the wall, which did not belong to either of them....