After almost drowning in a lake accident, Madison (Michelle Mylett, Antisocial) develops hydrophobia : an abnormal fear of water. After shutting the world and her friends out for over a year, her friends attempt an intervention. But, instead of curbing Madison's fear, they unknowingly unleash something far worse: The vision of serial killer turned supernatural psychopath Sebastian Donner - known as 'The Drownsman' - who begins to stalk the women one by one, dragging them into a lair of submerged torment from which there is no escape.