S1·E17 Revelations

A small girl has a horrifying experience at a private school and accuses one of the teachers of being a monster. As Rachel used to go to the school the headmistress calls her up to ask her for help. She hopes that Rachel will be able to find out what really happened before the school is ruined by the scandal. As she investigates Rachel realises that she has no memories of being at the school at all! She knows she went there but can remember nothing and that begins to really worry her.