When 17-year-old Ally moves into Larchwood Academy, a prestigious boarding school housed in an old manor house,she has to settle into a new life of friendship, romance, tradition, and mystery. One day, she visits an old church ruin near the school, where she happens upon the secret entrance to an underground room. Local lore has it, that the room was used for the practice of black magic in the 19th century. Soon after, the late mistress of Larchwood, Catherine Larchin, starts haunting her dreams in which she demands that Ally looks for an ancient spell book rumoured to contain a source of immense power. But when Ally learns that the school is also home to a secret circle of students in search of the book, she begins to wonder who of her new friends she can trust and who may be harbouring evil intentions.