ITV's long-running detective drama "Poirot" concluded in 2013 after 24 years and 13 series with an episode, "Curtain: Poirot's Last Case," widely regarded as its darkest instalment. The finale saw David Suchet's famously principled detective abandon his lifelong moral code, confronting a case that could not be solved through conventional justice and forcing him into an uncharacteristically extreme resolution.

In the episode, Poirot investigates Stephen Norton, a manipulator who orchestrates murders through others rather than committing them himself, leaving Poirot unable to prove his guilt through evidence. Convinced Norton would keep causing deaths, Poirot ultimately kills him himself before taking his own life, torn over whether the act was justified. The character is now set to return in a new BBC and BritBox series called "Hercule," starring Edward Bluemel as a younger Poirot, filming this summer and adapting three classic Agatha Christie stories including 1933's "Lord Edgware Dies."