Welcome to the castle on the hill.Twelve-year-old Casey has already lost more than most. When she's sent to live with her eccentric aunt in a crumbling mansion, she lets herself believe that it might be her forever home.Then she meets Megyn... who isn't like the other girls. Smarter, stronger, and far beyond any companion ever built, Megyn quickly becomes Casey's closest friend. But as her behaviors grow more unsettling, her creator must confront a devastating question: Is Megyn a marvel... or a monster?