The Big Four

In the fifth installment of Agatha Christie's Poirot series, an unexpected visitor collapses in Hercule Poirot's bedroom, cryptically repeating Poirot's name and writing the number 4. This leads to the revelation of an international crime cartel called "The Big Four," comprised of four enigmatic leaders from different backgrounds. Following the visitor's death, Poirot and his friend Hastings embark on a thrilling investigation to unravel the mystery behind this elusive criminal organization.