Fifteen years ago, Susan Morrow left her first husband Edward Sheffield. One day, comfortable in her home, and her second marriage, she receives, entirely out of the blue, a parcel containing the manuscript of her ex-husband's first novel. He writes asking her to read the book; she was always his best critic, he says. As Susan reads, she is drawn into the fictional life of his character Tony Hastings, a maths professor driving his family to their summer house in Maine. And as we read with her, so are we. As the Hastings' ordinary, civilized lives are disastrously, violently sent off course, Susan is plunged back into the past, forced to confront the darkness that inhabits her, and driven to name the fear that gnaws at her future and will change her life.