Something is lurking in the murky waters of Louisiana's swamplands, killing the unsuspecting locals, and medical examiner, Sam Rivers, and biologist, Mary Callahan, embark on a mission to shed light on the mystery. But, before long, another devastating attack leaves the team of investigators trapped in the hostile environment, fighting to survive the relentless onslaught of the methodical adversary. Now, blood stains the marshes. What's terrorising the bayou?
—Nick Riganas