Whispers Most Foul by Emma MacDonald

Rose Thenlif, an outcast at the elite Dunhollow Academy of Witchcraft for her inability to cast spells, keeps her head in books, away from the sneers of her talented but insufferable academic rival Sylvie.

But when classmates begin to disappear, Rose discovers that she alone can see their ghosts — and when Sylvie becomes Rose’s latest ghostly vision, the reluctant pair must team up to uncover the deadly mystery that lies at the heart of Dunhollow, before time runs out. But are either prepared to face the most haunting of secrets, one buried deep in both their hearts?