"A missing girl. A tormented witness. A web of lies. And someone is watching... When Ella Longfield overhears two attractive young men flirting with teenage girls on a train, she thinks nothing of it - until she realises they are fresh out of prison and her maternal instinct is put on high alert. But just as she's decided to call for help, something stops her. The next day, she wakes up to the news that one of the girls - beautiful, green-eyed Anna Ballard - has disappeared. A year later, Anna ...