Whether he's on holiday abroad, taking a countryside break or simply going about his business near his central London home, Poirot finds himself exercising his "little grey cells" by helping police investigate crimes and murders, whether they ask for his help or not.

He's often accompanied by his trusty sidekick Captain Hastings, and their paths cross Scotland Yard's Inspector Japp who has a grudging respect for the meticulous, if eccentric, private detective.