Im Yoona's life takes a drastic turn when she gets into an accident and loses her memory. She forgets the person she used to be, the person she married, but there is only one thing she remembers: her parents' murder. In a fit of vengeance, she knows that she has to find out who killed her parents and exact revenge in order to satisfy her thirst for blood. Determined to follow through with her plan, she finds out that her life is more brutal than she could ever imagine, her marriage is not as happy as she thinks it is, that her own husband, Lu Han, is possibly hiding secrets, that her own friends may not be trusted and that she is more horrible than people lead her to believe.