M. Night Shyamalan directs this psychological thriller starring James McAvoy.
Kevin (McAvoy) is a man who suffers from dissociative identity disorder, meaning that he exhibits numerous distinct personalities which affect his behaviour.
Kevin becomes driven to kidnap three young girls - Casey (Anya Taylor-Joy), Claire (Haley Lu Richardson) and Hannah (Kim Director) - on their way to a party.
While trapped, the girls witness Kevin's personality shift repeatedly and try desperately to figure out a way to escape.
Kevin has therapy sessions with Dr. Fletcher (Betty Buckley), who slowly realises that Kevin is on the verge of a devastating mental breakdown.
As she tries to convince her colleagues that someone with as serious a condition as Kevin can forcibly alter their physiology with their mind, Kevin develops a final, monstrous personality...