Acclaimed director Steven Soderbergh is no stranger to employing unique and abnormal methods to produce films, and his latest film definitely followed  a different path. Unsane, his new film shot entirely on an iPhone, now has its first trailer.

After bursting onto the scene at age 26 with 1989’s Sex, Lies, and Videotape, Soderbergh has made a litany of unorthodox movies, including the surreal pseudo-biopic Kafka and films like Schizopolis and Bubble, which defy traditional narrative structure. With Unsane, hitting theaters in March 2018, Soderbergh is up to his old tricks — or, more accurately, he’s breaking out some new ones.

Soderbergh shot Unsane on his iPhone (no, we don’t know what model). It follows a young woman played by Golden Globe winner Claire Foy (The Crown) who is involuntarily committed to a mental institution and confronted by her greatest fear. The film’s trailer touches on themes of stalking and mental illness, and makes it uncertain whether Foy’s character is actually delusional or the victim of some terrifying, diabolical plot.

Along with Foy, the film’s cast includes Joshua Leonard (The Blair Witch Project), Jay Pharoah (Ride Along), Juno Temple (Sin City: A Dame to Kill For), Aimee Mullins (Stranger Things), and Amy Irving (Traffic).

Soderbergh has been fairly busy of late. His action heist pic Logan Lucky was released in August to general acclaim, and a “secret project” that he’s been working on for years recently came to light. That project is Mosaic, an HBO series with a branching narrative (think “choose your own adventure” books, though Soderbergh scoffs at the comparison) that viewers can control via a mobile app. Mosaic represents yet another stab at unconventional filmmaking, displaying Soderbergh’s willingness to push boundaries.

Bleecker Street, the distributor behind Logan Lucky, will reportedly seek a wide release for Unsane, which will compete with Pacific Rim: Uprising when it’s released March 23. Other movies hitting theaters the same weekend as Unsane include Wes Anderson’s Isle of Dogs and Paramount’s animated comedy Sherlock Gnomes. As with Logan Lucky, Soderbergh is overseeing marketing — a rare occurrence for directors — and distributing it through his Fingerprint Releasing imprint.

Update on January 29, 2018: We added the first trailer for the film.