Ex-Royal Marine commando Hunter is no angel. He drinks too much and loves women even more. His wife Jenny is carrying on her own affair with his best friend, Jock, and the mysterious landscape that surrounds the young family holds the kinds of dark secrets that create suspenseful folklore. When Hunter and Jenny decide to rekindle their love via an out-of-the-way weekend trip with their young son Carl, they drive into a quaint village, obviously untouched for hundreds of years. After encountering a gnarled old woman who gives them directions to a local pub, Hunter is excited by the chills that travel down his spine. Jenny just wants to go home. During a post-lunch stroll in the countryside, Hunter stumbles upon twelve standing stones. As he touches one of the stones, his hand is covered in blood and even more red liquid puddles around his feet. Suddenly, their son disappears from where they were picnicking and while on a frantic search to find him, Jenny and Hunter encounter a mythical monster like no other.
Hunter must fight for his life and the lives of his family as he desperately attempts to save them all from the Beast of Exmoor.