We have an exclusive clip from the upcoming thriller The Moth Diaries, which is currently available on demand via SundanceNOW, Cable VOD, Amazon Streaming, iTunes and XBox Zune ahead of its theatrical release April 20. Sarah Bolger and Sarah Gadon star as Rebecca and Lucy, best friends at an all-girls boarding school, whose lives are turned upside down by the arrival of Ernessa (Lily Cole). Check out this scene where Ernessa makes Rebecca uncomfortable by mentioning her father's death.

Acclaimed director Mary Harron (American Psycho, The Notorious Bettie Page) returns with the chilling story of Rebecca (Sarah Bolger), a young girl who, haunted by her father's suicide, enrolls in an elite boarding school for girls. Before long, Rebecca's friendship with the popular Lucy (Sarah Gadon) is shattered by the arrival of a dark and mysterious new student named Ernessa (Lily Cole). Lucy falls under Ernessa's spell and becomes emotionally and physically consumed by her glamorous new friend.

Rebecca, whose overtures of concern are rejected by Lucy, finds herself lost and confused. She begins to develop a crush on her handsome English teacher, Mr. Davies (Scott Speedman) and immerses herself in the Gothic vampire novel Carilla for his class. Rebecca starts to suspect that Ernessa is a vampire, but, despite the suspicious deaths that begin to occur, her fears are treated as simple girlish jealousy.

As the bodies of young girls pile up and the line between reality and the supernatural starts to blur, Rebecca decides to take matters into her own hands and get rid of Ernessa. Who can say what is real and what is unreal to the heart consumed by passion and a mind afire with loss? Based on the bestselling novel by Rachel Klein, The Moth Diaries is a harrowing story of the anxieties, lusts and fears of adolescence.