One of Agatha Christie's darkest and most sinister mysteries, newly adapted for BBC Television by the award-winning team behind And Then There Were None, Witness for the Prosecution, Ordeal by Innocence and The ABC Murders.When an elderly priest is murdered, the killer searches the victim so desperately that Father Gorman's already ragged cassock is torn in the process.But just what was the killer looking for? And what had a dying woman confided to the priest on her death-bed, only hours earlier?Maybe the three women, rumoured to practise the 'Dark Arts', who run the Pale Horse public house can provide the answers. Or maybe the solution lies in the darker side of human nature...