As Tara (Toni Collette) walks into her first Abnormal Psychology class, she transitions into her psychiatrist alter Shoshanna and begins lecturing her fellow students, only to be interrupted by the actual professor, Dr. Hattaras (Eddie Izzard), who uses Tara's incident to embarrass her in front of her classmates as well as to vocalise his scepticism about D.I.D (Dissociative Identity Disorder). At the same time, high school film students Marshall (Keir Gilchrist), Lionel (Michael Willett) and Noah (Aaron Christian Howles) set out to make a movie that their narrow-minded teacher won't soon forget.