At an elite boarding school for girls, troubled Rebecca (Sarah Bolger, The Tudors) and popular Lucy's (Sarah Gadon, A Dangerous Method) friendship is shattered with the arrival of a dark and mysterious new student named Ernessa (Lily Cole), whose captivating glamour lures Lucy into her company. Heartbroken, Rebecca develops a crush on her handsome English teacher Mr. Davies (Scott Speedman, The Strangers) and immerses herself in the Gothic vampire novel Carilla for his class. Before long Rebecca starts to suspect that Ernessa is a vampire, and takes it upon herself to rid the school of her presence. As the bodies of young girls pile up and Rebecca's passionate feeling of loss intensifies, the line between reality and the supernatural starts to blur with deadly consequences. Based on the bestselling novel by Rachel Klein and directed by Mary Harmon (American Psycho), THE MOTH DIARIES is a harrowing story of the anxieties, lusts and fears of adolescence.