After witnessing something shocking, Rachel offers what she knows to the police, and becomes inextricably entwined in what happens next, as well as in the lives of everyone involved. Has she done more harm than good?

"Nobody ever talks to strangers on the train. It's a rule. But what would happen if they did? From the New York Times bestselling author of The Authenticity Project, a heartwarming novel about unexpected friendships and the joy of connecting. Every day Iona, a larger-than-life magazine advice columnist, travels the ten stops from Hampton Court to Waterloo Station by train, accompanied by her dog, Lulu. Every day she sees the same people, whom she...