A serial killer is on the loose, murdering his victims in alphabetical order, leaving an ABC railway guide beside each body and playing a dangerous game with Hercule Poirot. He alerts Poirot in advance of the locations of the murders, but Poirot always arrives too late. Intrigued by the psychopath's mind and methodology, Poirot travels the length and breadth of England - determined to track down this ruthless killer.