Monster-slaying Stories

The C.O.P.S, the perfect organization for monster-slaying, people saving, and keeping important secrets secret... need help. After the normal police caught an elusive murderer that had no face and was dressed in white, they sentenced him to death by lethal injection. Unfortunately, that was one of the keys to unleashing an ancient evil, and the world became pretty much screwed after that. Can a boy from the year 1752 save the world? Or will evil finally win?