This is Lilly and Sarah's first book in their new series of book's . Case Closed is the first book in the series of Lilly and Sarah . In this book this is where the girls first meet each other . Lilly has to face a evil man who is the man that murdered Sarah . After he finds out that Lilly is looking into the case he starts to come after her . However just as he starts to go after her, Lilly meets Sarah . Sarah explains who she is and why she is here . She then becomes Lilly's Guardian Angel forever . Everyone thought Sarah was bullied to death at school . Lilly goes to the same school that Sarah went to . However Lilly is not about to be bullied by anybody . After Lilly brings the bullies around, which ends the bullying in the school . Lilly helps Sarah go after the man that murdered her . The detectives have closed the case . Lilly and Sarah have reopened the case themselves . Only Lilly knows about Sarah . Only the two girls can communicate, see and feel each other . As you will read in all of the Lilly and Sarah books Lilly and Sarah are no girls to mess with .