1933. Hercule Poirot (John Malkovich), 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. The new guard led by hot headed Inspector Crome (Rupert Grint) are not interested in his story. But soon there is a murder, and in order to have any hope of catching the killer, the once great detective must take matters into his own hands. In her fourth Agatha Christie adaptation, BAFTA® nominated writer Sarah Phelps (Ordeal By Innocence, And Then There Were None) brings Hercule Poirot and his little grey cells back onto our television screens in one of the most surprising and unusual appearances by one of literature's most iconic detectives.