What lies beneath the water has long been a valuable source of material for genre filmmakers. From monstrous sea creatures and sharks to aliens and even zombies, what lurks in the cold darkness of the deep has put fear into movie audiences for over 70 years. If the idea of a haunted pool seems rather silly, hold your breath. Bryce McGuire’s “Night Swim” plumbs the depths of ridiculousness, becoming a horror exercise void of scares and originality.

After selling the idea to James Wan’s production company Atomic Monster (who partnered with the unstoppable force that is Blumhouse), “Night Swim” is the feature length version of McGuire and Rod Blackhurst’s rather effective 4 minute chiller of the same name. The sad news being that, in this case, bigger is not better.

The always good Wyatt Russell is Ray Waller, a former Major League Baseball star, now suffering from the early stages of multiple sclerosis. Along with his supportive wife Eve (Kerry Condon) and their two kids Izzie (Amélie Hoeferle) and Elliot (Gavin Warren), the family moved into a big new house that has a swimming pool. As Ray uses the pool for his physical therapy (which sees him getting better abnormally fast), his family members have more terrifying encounters when in or around the backyard pool. Frankly, there isn’t anything more to the film, save for the mystery of it all, which is revealed in the film’s most absurd moment.

The main cast does well. Russell has a natural screen presence and has proven himself a fine actor, doing solid work here. Condon brings dedication to her portrayal of a mother who must step up and save her family. As the kids, Hoeferle and Warren give their characters a natural rapport, avoiding the pitfalls of Hollywood’s cliched portraits of today’s youth. Due to the actors’ dedication, we believe this is a believable family unit.

Regarding the myriad of ways this film fails, the fault lies in McGuire and Blackhurst’s screenplay. While expanding a less-than five minute short to feature length must certainly have its challenges, the filmmakers lose the atmospheric tension that made their previous work so effective.

The film doesn’t do enough to make an audience care for the Waller clan, merely skimming the surface of their backstory. There is jealousy from young Elliot, as his baseball skills are nowhere near his father’s and the boy wants to live up to his poppa’s reputation. I suppose the film wants us to sympathize with the young boy, but the root of his feelings aren’t explored. As for daughter Izzie, beyond the picture’s big moment (which the trailers use to sell the film), her presence in the scheme of things doesn’t seem to add much.

By the finale, the script throws everything AND the kitchen sink at the actors, until they drown in the ineptitude of a film with nowhere to go.

As for the horror, the filmmakers’ lack of originality prevents any scene from working. Despite Charlie Sarroff’s decent camerawork when the pool comes to “life”, nothing feels scary and there is zero tension to be had. After the fifth or sixth scene where a character floats in the water as the lights flicker and ghostly voices echo in the night, the experience becomes numbing. By