The vast labyrinth of caverns, passages and subterranean rivers beneath the Peak District are a major tourist attraction. But this summer not all the darkness is underground, and not all the devils are folk legends. Mingling with the holiday-makers is a convicted killer, bent on revenge.
Fourteen years ago, Mansell Quinn, was sentenced to life imprisonment for the murder of his lover. Now he's out under licence, whereabouts unknown, and his ex-wife has been murdered.
As they try to anticipate the fugitive's next move, detectives Diane Fry and Ben Cooper become increasingly puzzled by the case. Why did Quinn's two friends refuse to back up his alibi? And why did nobody visit him in prison for the last ten years of his sentence? Nobody, that is, except one of those two friends: ex-soldier Will Thorpe, now living rough somewhere in the Hope Valley.