This story is set in Cambridge UK where we find that as it opens Katie is kidnapped. Katie is an angry teenager who stormed out of the house in the rain, and thus, according to many including the police, may have just run away. But we know better.
Margot, who writes the Dear Amy advice column for teenagers on the local newspaper and who teaches English at a private school, starts to receive letters. Letters written apparently by a child, posted the day before receipt, and yet the signature is of a girl, Bethan, who disappeared 20 years before.
All this is set against a time in Margot’s life where she is emotionally at sea. Her marriage has crashed and her mental state is fragile. But for some reason she decides to investigate the letters and Bethan’s disappearance.
You feel strongly Margot’s despair and deep need to restablish a stable life after her crashed marriage.
As the story continues a sense of menace grows – well described from Margot’s perspective as a person with anxiety disorders – and thus how much does she imagine? And how much is real?