Olive and her parents live in a large, old house where an evil woman once lived. The girl has few contacts with people, depending on her friendship with Morton, a child she met inside a painting, and the three cats who came with the house. But she no longer has the glasses that helped her climb inside the paintings and the cats have become even more aloof. Then a new character steps into her world: Rutherford, the grandson of a neighbor, brings his curiosity, his knowledge of all things knightly, and his vast holding of unnecessary information and offers his help. When he suggests to Olive that she should be looking for the family spellbook, or grimoire, the story takes off. Olive has been warned not to delve into these secrets for good reason, but she believes her desire to help Morton find his family is a more important reason. Soon after she finds the book, it appears that she has fallen under its control. And she quickly realizes that her neighbors may have hidden identities and plans. Olive will need all the help she can get to stay out of the way of the evil around her. The book concludes with a new problem for Olive, so readers will look forward to the next book.