Murder is a very simple crime
As easy as ABC

The whole country is in a state of panic.

There is a killer on the loose, growing more confident with each successive execution - Alice Ascher in Andover, Betty Barnard in Bexhill, Sir Carmichael Clarke in Churston - laying a trail of deliberate clues to haunt the world's greatest detective, Hercule Poirot.

Which might just be the killer's first mistake…