Exorcism - the expulsion or attempted expulsion of a supposed evil spirit from a person or place. Sarah was attacked and in self defence, she killed someone she knew. She was found guilty but she still attends school and lives out her life like a normal teenager but with conditions. She has to stay in a special room when not attending school, have a bodyguard at her side at all times and she must attend mind control classes as well as having a tracker locked onto her ankle. Not knowing what this means, Sarah demands to know what is going on and finds out that she has been possessed by an evil spirit that has never been killed in 300 years. Sarah is the only one that can kill the evil spirit so she has to learn how to kill it otherwise her body will be taken over by the evil spirit permanently.