During the october holidays Rose and her brother Rory are, with other teenagers, invited for a week in a traditional music school in northern Scotland.

As soon as they arrive, Nell the teacher turns out to be both strange and frightening. Cat, the green-haired girl who looks after the guests, is also mysterious.

One night, the group is awakened by music. Where is it coming from? Who is playing at such a late hour? Intrigued, the teenagers try to discover the secrets and the legend of the manor.