The Deep South is a world away from the Los Angeles lifestyle of slick screenwriter David Sumner (James Marsden), so when he relocates with beautiful wife Amy (Kate Bosworth) to her childhood home it is an exciting change. Enthusiastically he tries to integrate into the small God-fearing community of Blackwater, Mississippi. However, what he initially takes for friendly local interest soon becomes claustrophobic interference. In particular, Amy's beer-swilling high school boyfriend Charlie (Alexander Skarsgård), who David hires to repair their roof, brings an air of confrontation that leaves the couple on edge.
When Charlie and his burly foul-mouthed mates begin leering at Amy, David's nervousness turns to disgust and he decides to finally stand up against the uncouth locals. This only serves to fuel the flames of animosity and Charlie's tense dislike ignites into a murderous hatred.