Hercule Poirot met his lifelong friend, Captain Arthur Hastings, and solved the first of his cases to be published, "The Mysterious Affair at Styles". It is clear that Hastings and Poirot are already friends when they meet in Chapter 2 of the novel, as Hastings tells Cynthia that he has not seen him for "some years". Particulars such as the date of 1916 for the case and that Hastings had met Poirot in Belgium, are given in "Curtain: Poirot's Last Case", Chapter 1. After that case, Poirot apparently came to the attention of the British secret service and undertook cases for the
Hercule Poirot which Christie contrasts with Hastings' love of autos: this is shown in "The Plymouth Express", "The Mystery of the Blue Train", "Murder on the Orient Express", and "The ABC Murders" (in the TV series, steam trains are seen in nearly all of the episodes). That’s the way of it. Just a case or two, just one case more – the Prima Donna’s farewell performance won’t be in it with yours, Poirot. Confusion surrounds Poirot's retirement. Most of the cases covered by Poirot's private detective agency take place before his retirement to grow marrows, at which time he solves "The Murder