Title: Mediator - Volume 1 - Shadowland - Meg Cabot - book
Summary :
Susannah Simon is a medium. She connects the dead and the living. There's no rest for her: the ghosts demand that she complete what they didn't have time to accomplish on Earth. But when you've just moved to sunny California, you're a girl, and you're sixteen, you'd rather wander around malls than cemeteries. Alas, as soon as she arrives at her new high school, Susannah realizes that her life isn't going to be that simple. The ghost of a young high school girl has decided to take revenge. Susannah is standing in her way.
