The Big Four is a novel featuring Agatha Christie’s master Detective Hercule Poirot.

Poirot takes on a mysterious group of 4 supervillians bent on overtaking the world. The group includes the following : a Chinese political mastermind, an American tycoon, a French nuclear scientist and a British assassin and master of disguise. They are quite a formidable bunch.

Additionally, Poirot has to contend with Countess Vera Rossakov. She is in the employ of the big four. But, it is intimated that she and Poirot are more than just friends.This is one of the rare instances in the Poirot books where a love interest is mentioned or intimated.

Another interesting plot element involves an identical twin of Poirot’s named Achille Poirot.