The Alchemist's glass staircase

Karolina crossed the threshold of the apartment building on Kwiatowa Street. Her body trembled with excitement, even though she had been living here alone for weeks - her parents had left and she could dispose of the whole flat as she wished. Little did she know that there was something hidden under the boards in the hallway, right next to the stairs, that no one but her was meant to discover. One evening after a storm, she heard a quiet knocking under the floorboards. Karolina crouched down and pushed aside a row of oak planks. To her eyes appeared a narrow entrance leading into a dark, damp corridor. To her surprise, the staircase shimmered as if it were made of clear glass, and from below came the smell of lavender mingled with something far more mysterious. Unable to contain herself, she descended carefully. With each step, thicker and thicker vapours surrounded her. At last she stood in a huge underground laboratory. On the shelves, among leather-bound books, stood dozens of coloured vials and glass bubbles in which something was bubbling. Against the wall sat a man in a grey coat, with very long silver hair. His eyes glowed with a golden radiance, and in his fingers he was turning a small vial of fluorescent liquid. The man looked at Karolina and gestured her closer. "Weren't you afraid to go this deep? Are you ready to learn the secret of the Glass Steps?" he asked, and his voice vibrated with a strange power. Behind his back, in the alchemical furnace, something suddenly exploded, bursting into violet light....