Demián Rugna left an indelible mark on the horror scene in 2017 with the aptly titled Terrified, an expertly done paranormal story featuring one of the most unsettling children ever committed to film. His latest, When Evil Lurks, is a tougher proposition, but is further evidence that Rugna makes horror films, he commits utterly to that descriptor. A nightmarish, nihilistic amalgamation of folk horror, road movie, and possession shocker, it’s one of the most distinctive, brutal, and best of the year.

When brothers Pedro and Jimmy (Ezequiel Rodriguez and Demián Salomon) find the lower half of a corpse on the grounds of their remote farm, they trace it to the home of Uriel, who has become a bloated, oozing ruin literally pregnant with evil. Ignoring the insistence of the possessed man’s family that he needs to be properly exorcised, the brothers and local landowner Ruiz (Luis Ziembrowski) decide to dispose of Uriel away from the community. When the demonic host mysteriously vanishes en route, a viral outbreak of sickening violence is unleashed.

Rugna wastes no time setting up the lore and the rules of engagement. Within five minutes we’re engulfed in the thick of a very real and dangerous situation, one accepted pretty much instantly by everyone involved. The inhabitants of this region are familiar with these forces. It’s accepted that mendicant exorcists, or ‘cleaners’, are routinely employed to purify those unfortunates like Uriel. And nothing and no one is safe. Not animals. Not pregnant women. Not children. The human body in all its variants is there to be manipulated, twisted, and maimed in ways that will make the most ironclad stomachs quiver. The brilliance of Rugna’s film is in how often he surprises the viewer, how frequently the violence comes out of nowhere, and how he’s never afraid to turn the screw that little bit tighter each time.

Yet, it’s not a straight thrill ride. There’s a certain narrative aimlessness that comes with the road movie format – it feels like poor Uriel is a boulder hurled into a swamp, and we’re merely witness to the toxic ripples in the aftermath – but this fits the despairing tone beautifully. There are the normal beats of the possession movie, but there is never the sense that Pedro and Jimmy’s best efforts will be enough; they often feel as powerless to influence events as the viewer. Perhaps it’s the unspoken background of the region’s grinding poverty, or the implication that our protagonists may not be very nice people themselves, but beyond the sudden bursts of carnage When Evil Lurks pulsates with a grim hopelessness that lingers long after the shock factor of its set pieces.

There have been more consistently vicious films this year – Evil Dead Rise and Project Wolf Hunting for instance – but When Evil Lurks grounds its various outrages in a way where they play as charged allegory for a rancid world. It may not be as plausible as something like Speak No Evil, but it feels like a spiritual cousin, equally cold-blooded and pitiless. It’s unlikely to be a crowd pleaser, and some will be frustrated by its storytelling and lack of a rousing finale, but those who like their horror to be, well, horrific, will be enraptured by Rugna’s merciless vision of boundless evil.

Available to stream on Shudder now