100 Years of Detective crime novels from the Queen of Mystery An unexpected visitor called Mayerling comes in through Hercule Poirot's bedroom and collapses on the floor. The only clue to what he wants is his repeating Poirot's name and address and writing the number 4, many times. When Hastings jokingly calls it "The Mystery of the Big Four," the man begins speaking about an international crime cartel of that name. He describes the four leaders: Number 1 is a Chinese political mastermind named Li Chang Yen; Number 2 is probably American; Number 3 is a Frenchwoman; and Number 4 is known only as "the Destroyer." The man dies soon after Poirot and Hastings go off on the trail of the Big Four.
The Big Four, Agatha Christie's critically acclaimed book, reigns as the one of the supreme achievements of Agatha Christie's writing career - along with Death on the Nile, And Then There Were None, The Man in the Brown Suit, and Murder on the Orient Express - was first published in 1927. This quintessential classic mystery novel has been loved by generations of readers.