The ABC Murders - 1x01 - Episode 1- Followmy.tv

The story takes place in 1933 and sets the Belgian sleuth on the trail of a serial killer. The elusive murderer seemingly selects his victims and the locations of their deaths alphabetically, sending Poirot a series of taunting letters announcing his next move and leaving a railway guidebook at the crime scenes as a calling card. As he travels the length and breadth of the country, the detective finds his authority, his integrity and his very identity called into question.