Brimstone

Beneath our ordinary world lies a place of eternal eclipse, a place to which all evil creatures have been banished: This is Brimstone.
Brimstone: The Demon Within is a contemporary coming-of-age tale set in a treacherous realm that exists beneath our world. It’s the story of a gifted girl thrust into a wilderness of wonder and terror, where she’s forced to face her deepest fears and grapple with the dangers that lurk within and around her. We’ve teamed up with Hollywood screenwriter Will Simmons to create an epic dark fantasy universe.
Yet another unique cinematic novel from the creators of Fall of Gods.

You're welcome to check out the actual book yourself at http://moodpublishing.com/brimstone/