

is killing in locations where Poirot has previously been, when he discovers a newspaper clipping describing how he helped to deliver a baby on a train stopped in Andover. He telephones the home of Sir Carmichael Clarke to warn him, only to learn, he has already been murdered. It states that the next murder will be in the town of Churston. Poirot is given another letter from A.B.C. He believes that Poirot lied about his credentials and therefore cannot be trusted. A new letter arrives, stating that the next location and victim will begin with the letter C, but Crome still refuses Poirot's help.

Unbeknownst to Poirot and the police, a down-on-his-luck travelling stocking salesman named Alexander Bonaparte Cust encountered both victims prior to their deaths. However, he refuses all offers of help from Poirot and confiscates his papers, believing that Poirot knows the killer. When Alice Asher is found murdered, and she is quickly followed by Betty Barnard, in Bexhill, Crome takes the letters more seriously. Poirot seeks out Japp, but he suddenly dies in his presence. Poirot gives this information to the police, but Inspector Crome, who has replaced the retired Inspector Japp, dismisses the letters' contents as an April Fools Day prank. According to the letters, the first killing is slated to occur in Andover on 31 March. Poirot has been receiving letters signed A.B.C., taunting him and predicting murders. The De La Warr Pavilion at Bexhill-on-Sea in East Sussex is also featured. Newby Hall in North Yorkshire is the mansion at Churston. Various cities, towns and villages in the historic county of Yorkshire in the north of England-including Grosmont, Leeds, Pickering, Ripon, Saltaire, Skelton-on-Ure and Wakefield-played key roles as settings for this adaptation. Christopher Villiers as Sir Carmichael Clarke.
