Is this an original plot?

I'm thinking about writing a book from the view of a teenage girl that is accused of murder and is sentenced to go toi jail for the majority of her life even though she didn't do it. It will highlight some of the struggles that the girl goes through to try to prove her innocence and find out who the real murderer is. Throughout the story, while the girl struggles to uncover the truth about the real murderer, she is actually being watched very carefully by the real culprit that will go to great lengths to stop her from catching him and turning him in.