The first part of The Pale Horse set things up with all the deftness we have come to expect from Sarah Phelps’s Agatha Christie adaptations. It painted a stylish but sinister version of early Sixties England, a world of lascivious socialites and eerie village fairs and women who may or may not be witches. At the heart of it was Rufus Sewell as Mark Easterbrook, a philanderer with impeccable tailoring, a jaw you could use as an anvil, and a fat deck of dark secrets.