Une équipe de tournage de documentaire enquête sur une série de meurtres violents connus sous le nom de "meurtres de Black Water". Alors que leur investigation progresse, ils mettent à jour un terrifiant secret. Un de ceux dont ils ne réchapperont probablement pas...

Desperate for a break from big city life, Emma heads to her family's cabin deep in the Arkansas hills. As she settles in for some much-needed R&R, she learns that something unspeakable lurks in the surrounding darkness. As the full moon rises, a bloodthirsty werewolf emerges from the shadows, slaughtering everyone in its path and revealing a sinister underworld Emma never knew existed. Thrown into a fight for her life, and her very soul, Emma will need to escape these big bad woods before it's too late.