Welcome to Pine Creek, Missouri. Population: 8500. But that's not including the population of the hellmouth that lies below.
To an outsider, Pine Creek looks like your typical, small Midwest town but those who have grown up in Pine Creek and those with a special awareness know to be afraid of what lies below. You see, the small border town of Pine Creek, Missouri sits on top of a hellmouth. What exactly is a hellmouth, you might ask? A hellmouth is a location of increased supernatural activity. A hellmouth is an area in which the barriers between dimensions are weak. A hellmouth is the very portal between earth and Hell. For those who are aware; some choose simply to ignore the supernatural occurrences, some try to educate themselves and others so as to better be equipped to battle the evil, and some choose to get their hands dirty and slay the evil. Which will you be?
You can choose to be Watchers (these are the educators), Slayers (those who do battle), Evil Beings (demons, vampires, ect...) and even those unaware. You might have a college kid, a school teacher, a mechanic. It's up to you and anyone one of these people might live their daily lives under the guise of normalcy while spending their evenings watching and battling evil.