Netflix has released a new adaptation of Agatha Christie's 1929 novel "The Seven Dials Mystery" (retitled "Seven Dials"), keeping alive the near-century-long tradition of reinterpreting the crime writer's work. Unlike most Christie stories, this one features neither Hercule Poirot nor Miss Marple, and its release has prompted renewed interest in the very first film ever made from a Christie story, a 1928 British production that has since become something of a mystery in itself.

That film, "The Passing of Mr. Quin", was based on "The Coming of Mr. Quin", the opening story in Christie's collection "The Mysterious Mr. Quin", featuring an enigmatic recurring character she described as "not quite human" and "an advocate for the dead". According to its IMDb synopsis, the film's plot centres on a doctor proving his wife's first husband was murdered by a neighbour posing as a tramp, a significant departure from the more elliptical short story, in which Mr. Quin arrives at a house party and helps a guest solve a decades-old cold case. This was reportedly the first of many instances in which Christie adaptations strayed markedly from her original plots, contributing to her long-standing wariness of screen versions of her work.