When a serial killer stalks the small New England settlement of Grover's Corner during the fall of 1586, it falls upon the shoulder's of a holy man, Brian Dreamweaver, to save his brother's widow, her two small children, the good townsfolk of Grover's Corner, and if God is willing, himself. The Harbinger is an ancient evil, a forerunner to the gates of hell opening. The path of the Harbinger is documented in a single book; the Grimoire. This book was hidden within the Church of England until it mysteriously disappeared, but no one seemed to mind, after all what harm can come from a book.