Timothée Chalamet in a Gen Z cannibal romance? Delicious!

“What was your first time?” a pretty 18-year-old girl asks the dishily bedraggled young man sitting beside her in the pickup truck.

“It was the babysitter,” he answers, with a look that says “check out the living cliché”. “Mine too,” the girl coyly replies.

This duo, Taylor Russell’s Maren and Timothée Chalamet’s Lee, are swapping stories of a certain pivotal coming-of-age moment in both of their lives – and no, it isn’t that. The two are cannibals, born with a hunger for human blood and sinew, and their lives – rootless, precarious, on the margins – are little more than a touch-and-go stumble from one feed to the next.

In other words, they’re monsters. But in the eyes of Luca Guadagnino, the director of Call Me By Your Name and Suspiria, they’re also a classic example of that countercultural cinematic staple, the young lovers on the run – less a pair of junior Hannibal Lecters than Bonnie and Clyde with unusual appetites.

Bones and All is the Italian filmmaker’s piercingly romantic and at times gruesome adaptation of a 2015 young adult novel by Camille DeAngelis, which premiered at Venice this evening. Billed as a love story rather than a horror film, it’s by no means overloaded with gore, though one early out-of-nowhere bite shot had the 8.30am festival audience retching and pawing at their mouths. The later killings are equally strong stuff, though the violence stems more from Guadagnino and his editor Marco Costa’s fang-sharp, Psycho-like cutting than graphic excess.

After the release of Call Me By Your Name, Guadagnino was criticised by some for delicately panning away from one of Chalamet’s love scenes. Here – as if to demonstrate the point – the director takes both approaches at various junctures, and each proves mercilessly effective. When veteran Sully (Mark Rylance) gets on his elbows and knees to gnaw at the body of an elderly victim, the camera pans across her personal effects and family photographs on a nearby dresser – a perspective which somehow feels more horrible than a full-frontal feast shot.

It’s Sully who initially takes Maren under his wing when she’s abandoned by her father (André Holland) after years of midnight, law-evading relocations. (“Eaters”, as they call themselves, can smell out their own kind.) But she soon finds a truer kindred spirit in Chalamet’s Lee – a charismatic drifter in a crumpled shirt and jeans torn to shreds. Russell, a revelation in Trey Edward Shults’s under-seen Gen-Z melodrama Waves, is career-makingly good here, while Chalamet’s tender, tousled allure and razor-edge of raw danger powerfully recall the late River Phoenix: his Lee is a hustler to the core, always calculating where his next meal is coming from, and who he’ll have to sink his teeth into in order to get it.

Guadagnino’s regular screenwriter David Kajganich skilfully evokes that state of drifting need, while works every imaginable metaphorical angle: forbidden subcultures, drug addiction, folie à deux romance. But he can’t quite neutralise the novel’s lumpier plot manoeuvres, particularly those concerning Rylance’s character, who becomes more like a stock villain – and therefore less threatening – as the film proceeds.

The real lasting chill here comes from Michael Stuhlbarg, who floods the film with numbing dread in barely 10 minutes as a seasoned cannibal who tracks the youngsters to their campsite with ambiguous motives. Filling them in on some community slang, he explains that “having your bones” is the no-way-back moment when you first devour an entire corpse, leaving no trace behind. Maren looks equally disgusted and dubious. This must surely be a myth told to spook younger eaters? But in the dancing half-light of the campfire, it seems sickeningly possible.

In cinemas now