A weekend at Sara's (Sara Paxton) lake house in the Louisiana Gulf turns into a nightmare for her and her six other friends after one of them (Sinqua Walls) stumbles from the salt-water lake with his arm torn off. Assuming the injury was caused by a freak wake-boarding accident, the group realizes they have to get Malik to a hospital on the other side of the lake, and fast. But as they set out in a tiny speedboat, the college friends discover the lake has been stocked with hundreds of massive, flesh-eating sharks.