In their second collaboration, director Olivier Assayas and actress Kristen Stewart have created a mysterious, spooky and cerebral horror movie that not only concerns itself with things that go bump in the night, but also loneliness, grief and the need to escape oneself. Personal Shopper might frustrate those looking for a more straightforward genre exercise that purposefully doesn’t wrap its storylines up in neat bows and culminates in one of the great open ended finales of recent memory, but filmgoers seeking a thought provoking, distinctly European and often creepy horror movie will be duly rewarded.

As the picture opens, Stewart’s Maureen is pulling double duty as she examines an abandoned country home in France. Maureen is a medium and she’s scoping out the place for potential buyers who don’t want to live in a haunted house, but she’s also attempting to make contact with her twin brother, Lewis, who died several months prior in this particular house due to heart problems. When asked by others what she is doing in France, Maureen cryptically answers, “I’m waiting,” and we know that it is a sign from her dead brother for which she is holding out hope.

However, what Maureen is technically doing in France is working as a personal shopper for a high maintenance model named Kyra (Nora Von Waldstatten), who is hilariously introduced in the middle of a phone call in which she is bickering over a plan to save endangered gorillas. Maureen travels to high end stores in France – and even London – to pick out expensive outfits for Kyra and, despite being told not to, trying them on herself when no one’s looking.

Maureen has a boyfriend who is currently working in Oman and she occasionally takes part in video chats with him. She also has a few other friends who are practicing mediums. Otherwise, Maureen is primarily alone, despite being surrounded by faceless strangers as she walks – or often rides via scooter – the streets of Paris. Personal Shopper is a ghost story, but in more than one sense of the word – Maureen is haunted by the death of her brother, the non-present Kyra (who only makes one appearance) has an apparitional presence in the story and Maureen herself is clearly ignored by Kyra as she were a spirit.

In Assaya’s previous film, the marvelous Clouds of Sils Maria, Stewart also played an assistant to a well-known person – in that case, an actress played by Juliette Binoche – and approximately two-thirds of the way into that film, her character literally vanishes into thin air. In Personal Shopper, Stewart may be tracking a ghost – or more than one, for that matter – but she’s spectral herself.

A number of elements come into play to possibly throw the viewer off guard – Kyra’s boyfriend pops up in an early scene where he appears innocuous and a later one where he’s sinister, a brutal murder takes place and, during one of the picture’s most ingenious moments, a ghost may or may not be riding a hotel elevator and exiting its front door.

But the film’s centerpiece is an epic length conversation carried out via text between Maureen and a mysterious figure. Could it be the ghost of Lewis finally making contact with Maureen? Or has she summoned another otherworldly presence? Perhaps it’s neither, but rather a real-life stalker who appears to be tracking her every move.

Although one of the film’s storylines appears to come to a conclusion, it also opens the door for the film’s mysterious ending, which possibly changes the nature of the story if taken literally or adds further depth to the picture’s themes of solitude and mourning if taken figuratively. The final line that Stewart half-whispers halfway around the world from where the movie began will, regardless, leave you with much to ponder.

Assayas is one of French’s finest filmmakers, from his 1990s output (Irma Vep and Late August, Early September) to his more recent pictures (Sils Maria and the remarkable Carlos). Personal Shopper bears some similarity to his jet-set thrillers Demonlover and Boarding Gate, but it’s also unique in that it’s a rare example of the director directly taking on genre material, albeit blending horror scares with some of the themes that have long been present in his work.

And Stewart’s work here proves that she is a long way from Twilight. Between her work here and her previous role in Sils Maria – for which she became the first American actress to win a Cesar – it’s clear that Stewart is a gifted actress and a terrific muse for her French collaborator. This is a fascinating film for the cinematically adventurous.