A man stands bewildered on a deserted beach on the Hebridean Isle of Harris. He cannot remember who he is. The only clue to his identity is a folded map of a path named the Coffin Road. A detective from Lewis sits aboard a boat. DS George Gunn is on his way to find a bludgeoned corpse that has been discovered offshore. A teenage girl lies in her Edinburgh bedroom, desperate to discover the truth about her scientist father's suicide. She does not yet know his secret.