1933. Hercule Poirot, older and greyer, receives letters threatening murder. The sender signs themselves only as “A.B.C.” When he takes the letters to the police looking for help, Hercule finds all his old friends have moved on. But soon there is a murder and the once-great detective must take matters into his own hands.

As Hercule Poirot enjoys a luxurious cruise down the Nile, a newlywed heiress is found murdered on board and every elegant passenger becomes a prime suspect.

In 1935, when his train is stopped by deep snow, detective Hercule Poirot is called on to solve a murder that occurred in his car the night before.