This is the story of how I became my sister…
When troublesome Scarlet mysteriously disappears from Rookwood School, terrifying Miss Fox invites her quiet twin sister Ivy to ‘take her place’.

Ivy reluctantly agrees in the hope of finding out what happened to her missing sister. Only at Rookwood will Ivy be able to unlock the secrets of Scarlet’s disappearance, through a scattered trail of diary pages carefully hidden all over the school.

Can Ivy solve the mystery before Miss Fox suspects? Or before an even greater danger presents itself?

The first in a mesmerising boarding-school mystery series, with five more brilliant books to discover.