Lena's biological clock had always been a little off, as if city life forced her to be a night-marker. That night, as she walked back to her boarding school through the courtyard of the old high school, the air was heavy with the smell of rain and the lights of the lanterns slipped across the wet slabs of pavement. Lena should not have taken the shortcut through the south wing - stories had been circulating about it for years. Some said the old door led straight to the cellars, others whispered about mirrored corridors that only appear once every hundred years. This time she took a chance, feeling an unsettling courage within her. She found an old door, covered in a greenish tarnish. They gave way heavily under the pressure of her arm, creaking ominously. It was cooler inside, she could feel the dampness and something else - like electricity in the air. She reached into her pocket for the torch from her phone, but the light only deepened the shadows. To her right, she noticed a wall covered with cracked mirrors. Only after a moment did she notice her reflection, but it was... different. The reflection was smiling, although Lena was deadly serious. Suddenly, she heard quiet, broken laughter and a determined step behind her. She froze, trying to decide what to do. Then her reflection made a slow movement with her hand, as if inviting her to step into the wall. At the same moment, the door behind her slammed shut with a bang and the phone light began to flash. Whispers, growing clearer, mingled with Lena's own thoughts, leading her towards the centre of the corridor. Halfway down, she spotted another figure - it was a boy from her class, Michael, who had disappeared from boarding school a few weeks earlier. His reflection moved in the mirror behind him, but didn't follow him very closely. Lena felt the ground move out from under her feet and the air ripple. Suddenly, a third figure emerged from the mirrored surface, an older woman with eyes glittering with silver sparks. Her voice echoed: "Only one of you can return. Which will choose the key and which will choose the mirror?"