At night, the city took on a different rhythm. The lights of the street lamps on Sławkowska Street cast long shadows on the wet pavement, and the metallic clatter of trams came from afar. In the Jagiellonian Library, where centuries-old volumes hid stories as old as the Krakow air itself, Lena searched the shelves. She was an art history student in her final year, fascinated by the legends of the magic hidden beneath the city. That evening she had a head full of unfinished essays and tests, but something was leading her deeper into the library. The door to the underworld, usually closed, this time squeaked under her touch. Her heart fluttered like a bird - after all, it was forbidden to go down there. The stairs led deeper and deeper, under the damp vaults. Lena switched on the phone and immediately saw something unusual: in the middle of the cool hall, a reddish circle glowed, as if made of glowing powder. The drawings around its periphery resembled runes she had once seen in forbidden books. The whole room pulsed with a quiet, barely perceptible tremor. Lena tiptoed closer, and then the door behind her slammed shut with a bang. Sparks flashed in the circle. A figure emerged from the darkness - a young man in a black cloak with serpent-like embroidery. His eyes glowed with a silvery light. In his hands he held an old book and looked straight at her. "You have found our circle," he said in a voice that vibrated in her ears. "But are you ready to learn its secret?" Lena felt the chill of the underworld mingle with the heat of unknown magic, and the answer was to be brought by the night that was just beginning....