Sarah Phelps (The ABC Murders) is becoming the preeminent adapter of Agatha Christie. Her skills are best when she sticks close to the original material, as she did for Ordeal By Innocence. But when we she veers from that material, like The ABC Murders, the work is less worthy. It should be noted that she also works outside Christie’s ouvre, with intriguingly built adaptations like Dublin Murders. In other words, the writer/creator has chops.
The Pale Horse is one of those lesser known, rarely (if ever?) produced stand-alone Christies. Previous incarnations of it dragged it inappropriately into the Marple or Poirot worlds, as I recall. It is, as a book, still in the cozy category, with a pair of intrepid lovers discovering and solving a string of murders. Phelps reconceives the tale as something closer to Turning of the Screw crossed with Crime and Punishment, bringing it squarely into the psychological horror arena and putting the lovers at odds with one another. It has a highly stylized presentation, with a lot of creep factor; think Midsommar (the horror film, not the series).
Led by, and generally through the eyes of, Rufus Sewell (Judy), the story begins as a dark mystery of loss and fear and spins out from there. As a horror story it is effective, if not entirely satisfying by the end. Kaya Scodelario (Maze Runner: The Death Cure) gets to stretch her muscles into a role that is more adult than teenager for the first time. Her stressed 60s housewife is both darkly funny and depressing. Sean Pertwee (Gotham), on the other hand, gets somewhat abused as Inspector Lejeune. And Bertie Carvel (Jonathan Strange & Mr. Norell) has some fun in the mix, getting to wear a pair of the ugliest dentures ever seen on TV. But, generally, all of the cast do well filling out the world, victims, and those pulling the strings.
Perhaps part of the delivery gap of this series is down to young director Leonora Lonsdale. This is only her second full-length delivery. While the result, absent context, is fun, she allowed Phelps script to lead her too far astray from the source material. Depending on your relationship with Christie, your opinion and enjoyment of the story will vary. It is definitely not a light tale of murder on the green, but it is a complicated and layered tale of loss and greed, with just a suggestion of the supernatural.
[Updated 15 April, 2020 with a link to an interview with writer Phelps on Christie generally and her choices for Pale Horse]