Dear Amy: Helen Callaghan

Would you risk your life to save a stranger?

A local schoolgirl has been missing for weeks when Margot Lewis, agony aunt of the 'Dear Amy' advice column, receives a letter:

Dear Amy,
I've been kidnapped by a strange man.
I don't know where I am.

Please help me,
Bethan Avery

This must be a hoax. Because Bethan Avery is another young girl, who went missing twenty years ago.

As more letters arrive, Margot becomes consumed by finding the sender and - unlike the police - convinced that the girls' disappearances are connected.

Solving this puzzle could save someone's life - but could it also cost Margot her own?