The idea appeals to Hercule Poirot's vanity. Before he retires to grow superior vegetables, he will undertake just twelve more cases. All of them will resemble the remarkable feats of strength performed by that hero of ancient Greece, the first Hercules, but using brain instead of brawn.
Volume 46 in the Agatha Christie Collection (1947) Limited edition of 800 copies worldwide In appearance Hercule Poirot hardly resembled an ancient Greek hero. Yet -- reasoned the detective -- like Hercules he had been responsible for ridding society of some of its most unpleasant monsters. So, in the period leading up to his retirement, Poirot made up his mind to accept just twelve more cases: his self-imposed 'Labours'. Each would go down in the annals of crime as a heroic feat of deduction.