Bryce McGuire’s first feature, Night Swim, is an adaptation of his award-winning short film of the same name, and it has a disarmingly brilliant premise: what if a swimming pool was the locus of suburban horror? After all, pools have long been a part of the genre, from the steam rising off the surface of the pool at the start of Scream to the pool that alerts the family to a supernatural presence in Paranormal Activity 2. Going further back, I remember visiting the houses of friends who had pools and feeling the distinct otherness of this liquid presence in their backyard, especially when it was couched in trees, greenery and tasteful landscaping. Night Swim also situates the pool within the syntax of classical suburbia, opening with a family – Ray (Wyatt Russell) and Eve Waller (Kerry Condon) and their children Izzy (Amelie Hoeferle) and Elliot (Gavin Warren) – who decide at the last minute to forego their purchase in an upscale gated community and instead opt for an old-school suburban house, with a big pool.

It soon emerges that the pool is haunted, which turns Night Swim into a typology of all the ways a pool can be scary. From a distance, this pool is threatening, amorphous and otherworldly, refracting light up at the house. There are also scenes that focus on the eeriness of being underwater, as when objects are thrown in unexpectedly, or the eeriness of almost falling in, as when characters precariously reach out to recover objects floating on the surface of the water. McGuire also takes us through many different iterations of the pool: pool party, solo day swim, flirty night swim, doing laps and pool therapy. However, the most compelling horror revolves around the sightlines generated from and by the pool – glancing out at it through the window of the house, looking up through the surface of the water from the bottom, half-glimpses of the edges of the pool when doing laps, and the generally limited perspectives that come when you’re in a pool, sunken several feet below the rest of the yard.

Despite the title, Night Swim works best as daylight horror, evoking a crepuscular world beneath the water, a dimmer and cooler substrate to suburban normality. We learn that the pool is fed by a groundwater spring, and that the suburban tract was once a mineral springs resort whose thermally heated water drew people for its natural filtration and cleansing properties. That sense of a deeper subterranean liquidity intensifies the odd sense of spatial freefall and vulnerability that always comes with being alone in a pool in the middle of the day – the sense of being just below the horizon of safe visibility, proprioceptively awry. All of these qualities quickly contour the family drama, since Eve is scared of pools, and Ray is suffering from a neurodegenerative disorder that requires water therapy. Immersing himself in the pool takes the strain off his muscles and restores his sense of mobility, even as it imbues the pool itself with the off-balance qualities of his condition. Nevertheless, the family rallies around the pool, and their first collective event in their new home is cleaning and refilling it.

This relationship between the pool and the family revives an older suburban horror trope – the father being replaced by a new technological presence in the household. Once upon a time, that took the form of a discrete technological object, but no single object, not even smart phones, can encapsulate our dispersed digital milieu anymore. Instead, paternal and parental authority has been displaced by an ambient digital fluidity, so the swimming pool makes sense as a horror trope here, especially because McGuire focuses on the pool’s interfaces between liquidity and mechanical technology: the pool cleaner, the filter at the bottom, and the filter on the sides. These thresholds capture our current world more than any other site in the film, evoking an ambient digitality that coalesces uncanny around mechanical ports. In addition, horror films now have to contend with an ultra hi-def world whose pellucidity means that obscurity cannot be a feature of the screen image anymore either, at least in a fim that wants to remain urgently contemporary. Night Swim also addresses this situation in that the scariest space in the film is also the clearest, even though McGuire does restore some provisional graininess when Elliot sets up a camcorder to record the pool, in a nice throwback to the pivotal role that the pool plays in Paranormal Activity 2.

At one level, the pool arrogates the role of the father here. Ray encourages Elliot to throw coins into the pool, and then dive for them, but the pool intervenes, and throws the coins in his place. However, the pool also “identifies” with the father, if that makes sense, entering into a symbiotic role with Ray by rejuvenating him far beyond what is expected from regular water therapy. In fact, the pool reverses his neurodegenerative condition, reinforcing his stature in the household, and once again turning him into a superhero in his son’s eyes. Both Elliot and Izzy quickly deduce that there is something wrong with the pool but they tacitly decide not to say anything because it is having such a beneficial effect on their father. The overall effect is not unlike Jack Nicholson’s transformation in The Witches of Eastwick – positive on the whole, to be sure, but increasingly laced with an unsettling maniacal intensity.

It’s at this point that Eve starts to investigate the history of the pool, by tracking down the previous owners of the house. I love these investigative forays in suburban horror, in which wives embark on a neo-noir side-hustle to look into why their husbands have gone astray – think Melanie Griffith in the third act of Pacific Heights, or Michelle Pfeiffer in the second act of What Lies Beneath. The execution is not as brilliant here, even if the concept is terrific – the spring beneath the pool satisfies deepest desires, but once awoken requires a life to keep giving. It turns out that this nefarious wishing-well has been consuming people throughout the twentieth century, taking on a particularly rabid intensity once it was transformed into a swimming pool. Like “The Ones Who Walk Away From Omelas,” someone has to pay for the continuity of suburban normality, and in this case it turns out to be the father, as Ray sacrifices himself to the larger father-function of the pool. The ending is not all that well executed, partly because McGuire takes us deep “into” the pool, removing the threshold with suburban infrastructure that made it so eerie. Still, some eeriness remains, and in some ways the concept exceeds the execution here more generally. At moment it’s creaky but there is real franchise potential to Night Swim – a whole world of pool encounters waiting to be explored.