Ralph and Anna Eldred, a couple dedicated to social work in 1980s Norfolk, find their carefully constructed lives unraveling as the suppressed trauma of their past in Africa resurfaces. While they operate a trust for troubled youth, the couple remains haunted by the unexplained disappearance of their son decades earlier in Bechuanaland. The narrative shifts between their present-day efforts to rehabilitate offenders and the colonial-era memories that define their psychological landscape. Mantel employs a dual-timeline structure to examine how the weight of an unresolved tragedy dictates the moral choices of the present.

This novel is often noted for its sharp, unsentimental examination of the psychological burdens carried by its protagonists. The narrative is frequently praised for its ability to weave together disparate time periods without losing the tension of the central mystery. Readers often highlight the author's skill in portraying the moral ambiguity of the couple's altruistic endeavors. The work serves as a study of how past secrets can quietly erode the foundations of a seemingly stable life.