The Gateway by Z. Martin

Jonas has always been a wanderer, roaming from one corner of the world to the next in search of a purpose that has eluded him for a lifetime. But everything changes when he crosses paths with Eli, a stranger with a chilling secret.

Drawn into a world shrouded in fear and horror, Jonas is confronted with a mysterious book that holds the key to a destiny he never asked for. As the shadows close in around him, he must make a choice that will alter the course of his life, even though he doesn't fully understand the task at hand.