Encounter with the girl in the mirror

In all of my life, I had never once gone into the attic of the first Reine estate. Auntie Val forbade me from ever venturing into the old building, but by the night of my twelfth birthday, which was unusually warm for the season, I decided I was old enough to do so. All the adults warned me of the supernatural, but, being the foolish child I was, I didn't listen. As I pulled the cloth from the mirror of Elizabeth Reine III, I saw what I can only describe as a scientific impossibility...