At the edge of the Pennine Moors, Detective Sergeant Blackshaw and his rookie colleague, Detective Constable Lumb, are called to the scene of a double murder committed on a burial ground.
Amid a chain of unexplained deaths, Sergeant Blackshaw attempts to unravel.
Desperate for career advancement and obsessed with solving the mystery, DC Lumb immerses himself in the group - and soon disappears.
They discover that the case is connected to an ancient Celtic cult, in the remote village of Pen Crags.
At the edge of the Pennine Moors, Detective Sergeant Blackshaw and his rookie colleague, Detective Constable Lumb, are called to the scene of a double murder committed on a burial ground