I’m on Substack now! You can read this for free. https://substack.com/home/post/p-172703656
From Joe's writing

Like Ben, Katy had supernatural powers that were passed on to her because of a magical battle her father had been involved in years before she was born. She could enter other people’s dreams and control them, and, when she entered a hidden room on the third floor of the very building she was in now, she could alter the fabric of reality itself—but only in that room.

— A Pattern of Shadows, chapter 4