One of my greatest fears is to get submitted to mental institution against my will. That appears to be the same for Steven Soderbergh, whose next movie, Unsane, tackles that very subject. The first trailer just dropped and it’s a startling thriller as well as an interesting examination of a movie that was completely shot on an iPhone.

Soderbergh is known for directing the Ocean’s Eleven trilogy and winning Best Director at the 2001 Oscars for Traffic. With that kind of clout, you can direct just about any movie you want, and Soderbergh has taken full advantage of the perk.

With Unsane, Soderbergh shot the entire movie using an iPhone 7 Plus as his main camera. That was reportedly without any special rigs or lenses, just a gimbal for stabilization. The end result is pretty impressive.

Unsane is a horror thriller that explores the sanity of a woman (The Crown’s Claire Foy). Forced to seek help to get away from a stalker, this mysterious woman is accidentally admitted to a mental hospital where she cannot get out. If that isn’t freaky enough, her stalker ends up being her doctor. But then the question is asked: was she put into the asylum against her will or has she been there the whole time?

Unsane is in theaters March 23.