A few dead bodies do not a horror film make. And, traditionally, Steven Soderbergh does not a horror film make. Yet Unsane is being touted as a fright flick, which—if you accept the designation—marks the director’s first foray into the genre. It’s better to think of it as a psychological thriller, though, lest your hopes for a Michael Myers-style bloodfest be dashed.  

Unsane focuses on Sawyer (The Crown’s Claire Foy), a driven and no-nonsense woman who’s relocated to Pennsylvania from Boston to evade a stalker. She starts a new job and a new life, seemingly successfully—except when random shadows throw her back into her old nightmare. After an unsuccessful hookup ends in hysterics, Sawyer seeks some counseling, admitting that she never feels safe and, yes, that she has occasionally considered suicide. The counselor tells her that she needs to fill out some paperwork before making another appointment.

But instead of dealing with the receptionist, Sawyer is led through labyrinthine hallways, ushered into a small room, and told to strip. There’s been a mistake, she tells everyone she comes into contact with, “I have to get back to work.” The more she resists, however, the worse she makes it for herself: Sawyer has inadvertently signed herself in for a 24-hour commitment, and there are no takebacks.

Now, a film such as this one naturally requires some suspension of disbelief. But it’s here—not, as expected, in the ramped-up third act—that the plot by Jonathan Bernstein and James Greer (who last collaborated on 2010’s The Spy Next Door) turns implausible. Even if you accept that a smart person could mistakenly commit herself, Sawyer is treated ridiculously, sent to sleep in an open room whose several beds are occupied by patients with serious mental problems—no functioning individual with mild suicidal ideation would be placed with such a group. And that she almost immediately gets violent with both patients and staff belies a lack of judgment that doesn’t ring true for the character to whom we were first introduced. Desperate times? Perhaps. Regardless, Sawyer quickly earns herself a seven-day stay and becomes increasingly frantic when she thinks she sees her stalker at the hospital.

Soderbergh shot the entirety of Unsane on an iPhone, a choice that’s obvious from the first very-digital-looking shot. Like another iPhone baby, 2015’s Tangerine, the film is often hypersaturated, but, weirdly, in shades of beige and slightly yellowed beige. Once you get used to the aesthetics, the direction is mostly unremarkable save for a couple of disturbing, multiple-exposure effects that are amplified by a dissonant drone. Aside from the noise, the film is largely music-free, a good choice that helps the action feel like real life.

The British Foy is fierce as Sawyer. She makes the character palpably strong-willed, profane—so very far from the Queen—and someone you root for even when it seems as though her sanity actually is a little dicey. Juno Temple is unrecognizable and menacing as the patient in the bed neighboring Sawyer’s, and Amy Irving plays Sawyer’s mother without fanfare. It doesn’t matter much, though, because the show belongs to Foy and Joshua Leonard, whose role as the nurse Sawyer thinks is her stalker adds to the pantheon of mild-mannered creeps.

Even at a mere 97 minutes, Unsane feels long, though it’s never less than compelling thanks to Foy. Things do get murder-y, which is somewhat of a surprise at first but eventually feels like a natural progression. The film is an impressive step up for the screenwriters, whose previous scripts woefully involved Lindsay Lohan and Larry the Cable Guy. And Soderbergh? His un-retirement roll is continuing just fine.

Unsane opens Friday at Angelika Mosaic.