In 2011, Toby Soames dies from a freak accident on Hampstead Heath; Charlie Falk simply disappears. Two years later, Australian Adele Soames returns to London to be nearer her son and the places he loved. She is joined in her pilgrimages to the heath by Charlie. Charlie tells her things; unnerving things about his last day alive.
Enter DS Xandra Bentley, a member of Adele's grief support group at St Bart's. Xandra has worked on a number of cold cases of missing boys in the area and Adele's information reignites her interest. As new evidence comes to light, Adele has the creeping dread that she is bringing danger closer to home.