She's going through a divorce and rattled by the fact that one of her students, Katie, has gone missing. The police think Katie ran off, but Margot isn't so sure. When Margot receives a letter for her column purporting to be from Bethan Avery, a young girl who disappeared years ago, Margot thinks it must be a joke. But she also thinks of Katie and takes the letter to the police. When more letters show up, Margot is immersed upon a journey that will change her life forever--and endanger it in ways she could have never foreseen.