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.

John Malkovich, Rupert Grint, Eamon Farren, Andrew Buchan, Bronwyn James, Tara Fitzgerald, Anya Chalotra, Freya Mavor, Conrad McCroddan, Eve Austin, Suzanne Packer, Jack Farthing, Shirley Henderson