Based on the short film by Rod Blackhurst and Bryce McGuire (who also directed this feature), the film tells the story of Ray Waller (Wyatt Russell), a baseball star forced to retire early due to an illness that prevents him from playing. Trying to start a new life, he moves into a new house with his wife Eve (Kerry Condon), his teenage daughter Izzy (Amélie Hoeferle) and his young son Elliot (Gavin Warren). Secretly hoping to recover and return to professional sports, Ray convinces Eve that the fabulous backyard pool at his new home will be fun for the kids and serve as physical therapy for him. But, a dark secret from the house’s past will unleash a malevolent force that will drag the entire family into the unfathomable depths of the most suffocating terror.