It is 1942, and after a childhood of suffering in Birmingham, Maryann Bartholomew has built a life of happiness and safety with her husband Joel and their children, working the canals on his narrowboat, the Esther Jane. But the back-breaking work and constant childbearing take their toll on Maryann, and the tragic loss of her old friend Nancy, followed by a further pregnancy lead her to a desperate act which nearly costs her her life.

The walls of her security are broken down when Joel suffers an accident, and to keep the boats working, Maryann is forced to allow Sylvia and Dot, two wartime volunteers, into the privacy of their life. And when she discovers that someone keeps calling for her at Birmingham's Tyseley Wharf, the dark memories of her past begin to overwhelm her life. For that someone, who seems to be watching her every move, is becoming more dangerous that even she could imagine...