Trey Edward Schults retools horror movie tropes in It Comes At Night, a startling post-apocalyptic thriller suffused with paranoia

The big sick: Disease has decimated the population in It Comes At Night 

Ratings guide: WWWW - Wonderful  WWW - Worthwhile  WW - Watchable  W - Woeful

Please note: this review contains spoilers

It Comes At Night
Director: Trey Edward Schults
Starring: Joel Edgerton, Christopher Abbott, Carmen Ejogo
Running time: 91 minutes

There's a directness and an urgency about It Comes At Night that grabs you hard by the lapels in its first few minutes – all of which are disturbing – and doesn't let go again until its haunting closing shot around an hour and an half later. Like a catchy pop song that starts with a huge singalong chorus or a Formula One Grand Prix with a crash at its first corner, Trey Edward Schults' film gets right up in your business from the start. Those 90+ minutes fly by, too, barely giving you the chance to catch your breath.

We're in a dystopian post-apocalyptic America in which some sort of hideous virus has had its wicked way with the population (that's pretty much all you can surmise because hard info is thin on the ground). Those lucky/unlucky enough to have survived are seemingly few and far between; there are no more communities, just atomised families holed up in heavily-boarded houses tens of miles apart.

We first meet Paul (Joel Edgerton), Sarah (Carmen Ejogo), and Travis (Kelvin Harrison Jr) as they are taking an elderly man (Sarah's father, Travis's granddad) from their home, out into nearby woods. His skin is covered with lesions, his eyes black, he's bleeding copiously from the mouth, and, though alive, clearly has contracted whatever dreadful lurgy has prompted the family to don gas masks and thick gloves around him. Travis and Paul say their goodbyes, before the latter shoots him in the head, pushes him into a shallow grave and sets light to his body. Cheerio, grandpa!

As introductions go, this is a doozy, setting up an immediate sense of utmost jeopardy. Clearly, this is a world in which no one is safe. To survive, this seemingly loving family will sacrifice a beloved relative without breaking sweat. You wonder what they've had to do to still be alive at this point. We don't get much chance for such reverie, though, as soon the house has been broken into by another man – Will (Christopher Abbott). After initial fisticuffs, he is able to persuade Paul to allow him – plus his wife Kim (Riley Keogh) and young son Andrew (Griffin Robert Faulkner) – to move in with them. Alas, frictions born of paranoia, misunderstandings and madness quickly set the two families against one another.

The waking dead: Joel Edgerton versus the apocalypse

It Comes At Night borrows a lot of its moves from horror cinema but isn't really a horror film as such. If anything, it's a pure psychological thriller with its pitch-black corridors, flickering lanterns, creaking floorboards, and spooky woods really just there to help heighten the tension between the two families. If it reminded me of anything, it was perhaps last year's low-budget British indie The Survivalist, whose plot is almost identical (in a post-apocalyptic Britain, a woman and her daughter seek refuge with a potentially dangerous loner). This is a lot more polished than Stephen Fingleton's film, though, a lot less rough and ready, perhaps to its detriment because I believed in The Survivalist's blighted world more than I did It Comes At Night's, in which everyone (apart from the sick old man) looks surprisingly healthy.

Where Schults' film does win out, though, is in its exploration of these characters' mental and emotional states. What is the 'It' that comes at night? As it turns out, nothing physical or supernatural but delusion, exhaustion, insomnia and night terrors – a conglomeration of everything these poor bastards have suffered since whatever balloon went up resolving itself into a virulent fug of darkness and mental illness. Paul and Sarah's teenage son, Travis, is particularly affected by it all. He suffers terrible nightmares, draws disturbing images of skeleton creatures and creeps about the house when everyone else is asleep. At 17, he should be all about trying to hook up with cheerleaders and badgering his old man to buy him a car, not helping kill his granddad and teetering on the edge of a nervous breakdown. The way he looks at Kim is creepy and tragic all at the same time; rampant teenage hormones, his frustration and confusion tangible.

Humanity's penchant for paranoid self-sabotage is the oldest trope in the post-apocalyptic handbook but it packs more of a punch here than in anything I've seen in some time. Paul and Sarah have suffered such privation, been through so much shit, that they've almost forgotten how to be human. They find it impossible to trust people and have no idea how to empathise or communicate with outsiders, perhaps not even with their own clearly anguished son. All they can think of is how to stay alive, and if that involves harming or killing other people, so be it. There is genuine tragedy here as a result and Schults' writing and direction – plus some fine performances – ensure you feel every excruciating bit of it. It's no exaggeration to say the last 20 minutes are as riveting as any film I've seen all year, as we realise the director has performed a clever bait and switch – we've been watching the film from the bad guys' point of view all along.

It doesn't take a genius to work out that It Comes At Night is, in reality, a parable for worrying times, in which entrenched and mutually hostile political philosophies are a fact of life, especially in Trump's America and Brexit Britain. When we lose the ability to communicate with each other, when we fail to empathise with our neighbours, we're only a hop, skip and a jump away from real disaster is the film's clear message. The fact the director serves up such a downbeat ending suggests he's far from optimistic about our chances.

Rating: WWW½

It Comes At Night should still be in UK cinemas, if you're quick