Set in Wales, Death Valley follows the unlikely crime-solving partnership between eccentric national treasure John Chapel (Spall), a retired actor and star of hit fictional detective TV show Caesar, and disarming detective sergeant Janie Mallowan (Keyworth). Thrown together by the murder of John’s neighbor, John and Janie are an odd, yet hilarious duo with opposing instincts, and each week they get to the bottom of gripping murders.