After the final, haunting image of Personal Shopper fades out, the first credit to appear onscreen is that of the film’s star, Kristen Stewart. Her name appears in big, bold letters, as if to suggest that she, not writer/director Olivier Assayas, is the author of the film. It’s hard to argue otherwise, as she nails the kind of effective solo performance that only the greatest actors even attempt. Often alone onscreen, Stewart grounds the existential horror film in raw emotion she had apparently kept hidden beneath hipster cool and youthful affectation. For those grumps who refuse to see her as anything but the girl from Twilight, it is finally time to give up the ghost.

In her second collaboration with Assayas (following 2015’s Clouds of Sils Maria), Stewart plays Maureen, a young American in Paris grieving over the death of her twin brother. They had a deal, you see, in which whomever died first would come back to say hello from the great beyond. It must be a twin thing. All the living humans in her life recede into the background while she is consumed by thoughts of her missing other half. Maureen refuses to move on, physically or emotionally, until he fulfills his end of the bargain.

Her isolation, however, is also a practical matter. By day, she purchases clothes for her bitch of a boss, an aging model we see only in glimpses, and exchanges text messages with an aggressive secret admirer contacting her from an unknown number. Occasionally, she visits with her brother’s ex-fiancée, who has already moved on to another man. Maureen isn’t bothered by this, nor by anything else the waking world has to offer. She feels more comfortable at night, when she prowls various apartments (her own and her boss’), trying on clothes, drinking, and waiting for a sign.

Like the great works of Alfred Hitchcock, Personal Shopper is a film of two mysteries, a riveting spook story whose plot machinations serve as a clever distraction while the emotional subtext is carefully revealed. Throughout, Assayas embraces the conventions of the horror genre and enacts them with skill. He plays with oblique camera angles, creaky doors, and even blood-soaked sheets to keep your armrest tightly gripped and your nails properly bitten.

But the twists and turns of the ghost story are only sleight-of-hand. The narrative ingenuity is compelling—Personal Shopper keeps you guessing until the final shot, and perhaps even beyond it—while every scene digs deeper into Maureen’s grief. 

In the film’s claustrophobic frame, her placid loneliness is both an expression of her grieving emotional state and a horror movie trope. You may find yourself half-hoping for a ghost or even a killer to appear over her shoulder, if only so she could have some companionship. The shift from experiencing Personal Shopper as an exercise in genre to a richly-drawn character piece rests entirely on Stewart, whose thoughtful performance reveals itself so plainly that it takes a while to come into focus.

Her work here is revolutionary. Historically, the ingénue has existed in a state of permanent loneliness, playing to a camera that can never return her affections. Stewart, an anti-ingénue, finds a way around that problem. Yes, the camera lingers on her feline green eyes and often half-clothed body, but she refuses to acknowledge its existence. She remains oblivious to our watching, refusing to seduce us and instead inviting us to join her in the shared space. It’s a thrilling place to be. As Stewart investigates a ghost, she makes Personal Shopper bracingly alive.

Personal Shopper opens Friday at E Street Cinema.