Fifteen-year-old Emma Evans is like any other teenage girl. She thinks that her parents don't understand her. She longs for independence and a life free of family ties and responsibilities, and she is prepared to do anything to achieve it. But, one day she will be forced to face up to the consequences of her actions.
Emma starts experiencing frightening fits. Her parents are convinced that her problems are either medical or psychological, but when doctors' tests are unable to draw any conclusions, the family is forced to look elsewhere for answers.
It all started off as a bit of fun; Emma never really believed it, but the truth is there is something dark and sinister within her, and it won't take long to surface.