When Orla Payne was seven years old, her brother, Callum, mysteriously vanished from the Hanging Wood in the Lake District. Shrouded in complicated family matters and with no clear leads, the case was eventually dismissed. His body was never found. Twenty years of frustration and depression later, Orla is desperate to find out the truth. On historian Daniel Kind's recommendation, she contacts Cold Case Review detective Hannah Scarlett, who sets about seeking justice for brother and sister.