Whispers Most Foul - Dunhollow Academy, #1

Be wary of dark magic and the evil it carries. For when the hand of death enters Dunhollow Academy, no one is safe. Rose is a student at the prestigious and cutthroat institution of magical learning, Dunhollow Academy. The only problem is that she can't cast a single spell--something her chancellor mother and pretentious peers won't let her forget. Worst among them is Sylvie, the school's top caster, and Rose's academic rival. At the start of her third year, Rose must deal with not only the Academy's expectations of her, but the presence of a vicious ghost, Aveline-a first year student whose sudden and mysterious disappearance was covered up last term. Rose is the only person who can see Aveline's ghost, a secret she is keeping from everyone, even her best friend, Fen.
When Sylvie's ghost appears, Rose realizes that death is following the students at Dunhollow. Forced to team up, Rose and Sylvie find themselves tangled up in a web of old, dark magic and a dangerous secret Order. The deeper Rose and Sylvie search for answers, the darker the lies become. The clock is ticking, and Rose and Sylvie need to act fast before another student is claimed.