On his way to Istanbul, Hercule Poirot (David Suchet) is called back to London for a case, and finds transport via the opulent Orient Express train. An ornery American businessman, Samuel Ratchett (Toby Jones, MASTERPIECE CLASSIC “The Old Curiosity Shop), interrupts Poirot’s luxurious trip with a cryptic plea for help — he’s seeking penance, but may be murdered in the meantime. When the train is sidelined by a snowdrift and Ratchett is found dead, Poirot becomes embroiled in one of the most fiendish cases of his career. The suspects are numerous and colorful — an erudite Russian princess, an English colonel, a pushy American matron and a devout Swedish missionary, among others. The evidence suggests a shadowy assassin may have boarded the train during a stop in order to commit the murder, but is there an unforgivable evil even closer at hand? Based on the novel by Agatha Christie, “Murder on the Orient Express” features David Suchet as Hercule Poirot and an all-star supporting cast including Eileen Atkins (MASTERPIECE CLASSIC “Cranford”), Toby Jones, Barbara Hershey, Hugh Bonneville (MASTERPIECE CLASSIC “Downtown Abbey”), and David Morrissey (MASTERPIECE CLASSIC “Sense and Sensibility”). David Cumming hosts.