Claire Foy has the feeling she's being watched in the trailer for Steven Soderbergh's Unsane 

The trailer for Unsane, also known as “Steven Soderbergh’s iPhone movie,” has arrived, and it’s just as claustrophobic as you might expect. The scenario as it plays out in the trailer differs slightly from the initial summary of the film, which describes star Claire Foy as “a woman who voluntarily commits herself to a mental institution in order to confront her greatest fear.” Seeing Foy’s panic when she’s stripped and sent off to a mental hospital after telling a therapist about her stalker, it’s clear that the “voluntary” part of her commitment is highly subjective.

Unsane will unravel in theaters on March 23.