This may seem an unexpected point to make about an actor who is arguably one of the coolest people on the planet, but the key to Kristen Stewart’s mesmerising screen presence is her ordinariness. I don’t mean her looks, although as Lou, the manager of a bodybuilding gym in an insalubrious New Mexico backwater, Stewart’s natural magnetism is somewhat muted behind a whey powder pallor, an air of defeated weariness and hair that looks as if it’s been deep-fried rather than washed. Rather, it’s the unstudied, naturalistic quality of her performances, which are seeded with little glitchy details and gestures – the way she rakes her fingers through her fringe; the moment when she nervously wipes her nose on the sleeve of her T-shirt. Small things, perhaps, but these seemingly unconscious tics humanise her characters. They are recognisable, relatable moments of social awkwardness that anchor her in (or at least near) the real world. It’s a quality that adds to all her performances, but which is particularly invaluable in British director Rose Glass’s second picture, the deliciously lurid and thrillingly degenerate outlaw romance Love Lies Bleeding. When the rest of the movie launches itself headlong into outlandish, almost cartoonish excess, Lou is plausibly three-dimensional and grounded. The rooted realism that underpins Stewart’s performance offers a necessary balance to some of the more untrammelled impulses in Glass’s follow-up to her impressive debut feature, Saint Maud (2020). Another significant asset is newcomer Katy O’Brian, who shoulders what is probably the most demanding role in the film. Jackie is a bodybuilder from the kind of Godfearing midwestern farming country that views a “muscle chick” as an unnatural abomination. Blowing into Lou’s grim home town, more a collection of strip malls and casual violence than a functioning community, Jackie decides to hole up for a while and earn some money while she prepares for a bodybuilding competition in Las Vegas. She is a magnificent creature, glistening with confidence and physical assurance. It’s no wonder that Lou gawps across the gym, mouth agape, when she catches sight of Jackie, with her dark honey tan and a swarm of men preening around her. Eager to impress the new arrival later that evening, Lou scurries off into the office to fetch a box of steroid shots; she lays them in front of Jackie like an offering to a deity. The relationship that ignites between them is sweaty, grubby and scorching hot, but as the steroids do their work, warping and distorting Jackie’s body and her mind, a savage, self-destructive, simmering violence creeps into their romance. And this is where Lou’s sister Beth (Jena Malone) and her husband, JJ (Dave Franco), come in. At first glance the pair seem to be woefully underwritten, schematic cardboard cutouts rather than layered characters. She’s the battered wife; he’s the short-fused bully who takes out his inadequacy on his spouse. Concern for Beth’s safety is why Lou can’t bring herself to leave this spiteful small town, despite numerous reasons to do so (first of these being her gun-toting estranged father, played with reptilian menace by Ed Harris). But I suspect that Glass intends Beth and JJ to be more than just the dramatic device that unleashes the film’s dark heart and violent impulses. They also serve as a kind of twisted mirror image of Lou and Jackie’s amour fou and a cautionary warning that any relationship this thoroughly soaked in blood can’t, ultimately, end well, however invincible the partnership and the passion that drives it might seem at the time. And there’s a whole lot of blood, in a movie that embraces full-bore nastiness on every level. With the lip-smacking relish that she brings to the body-horror elements of the picture, and the sickening, sinewy crunches in the sound design, Glass ranks alongside the French director of Titane, Julia Ducournau, as one of the most exciting film-makers working in genre cinema. Both she and Ducournau share a heady, freewheeling independence in their approach and a healthy resistance to genre conventions. Both combine an appetite for gruesome excess with an impressive intellectual rigour. Love Lies Bleeding won’t be for everyone. I’ve watched it twice, and it plays rather better to an up-for-it, late-night audience than it does at 11am on a Sunday morning. But this is a movie that will find its people. And once it does, cult status is more or less assured. In UK and Irish cinemas now