The present day discovery of a child's remains in a peat bog south of Glasgow looks to finally solve the decades old mystery of ten year old Mary McInally's disappearance. Karen Marshall had been devastated by her best pal's abduction on the day of her confirmation. Questioned by the police but traumatised by the loss of her friend, nothing Karen remembered back then had helped. Now decades later, the news of the possible discovery of Mary's body brings the nightmares back, but added to that are returning memories long buried by Karen. Memories that begin to reveal her role in her friend's disappearance and perhaps the identity of the killer. Are these memories the truth or just a figment of an aging brain? Called in to excavate the body on the moor, forensic scientist Rhona MacLeod uses the advances made in forensic science since Mary's death to unravel a horrific tale that encompasses more than just one child, and not only in the past.