In 1933, retired detective Hercule Poirot starts to receive threatening letters signed "ABC". When he informs Scotland Yard, they ignore his fears, and soon enough, a series of killings begins.

A third murder leads to sensational headlines and ridicule for Poirot and Crome, who discover the connection between the murders and try to use it to work out who will be the ABC killer's next victim.

Poaro races against time to stop the bloodshed. Even when police believe they have caught the perpetrator, Poaro senses a new trick. Can he fulfill his lifelong debt to the dead, solve the mystery and learn the true identity of the killer?

With the ABC killer still on the loose, Hercule realises that only he holds the key to the murders. He faces a race against time to stop the bloodbath.