Final words of a dying man, lead Miss Marple and friends to investigate a dysfunctional family that has many secrets.. The film's story line is taken from a work of detective fiction by Agatha Christie, first published in the UK in September 1934 and in the United States in 1935 under the title of The Boomerang Clue. This is from season 4.
There is no plot, this is a travelogue/description of the actual Orient Express trains and trips and services/decorations/passenger treatment and comfort meant to guide viewers to an understanding of the train and it's handling of passengers. David Suchet is filmed on the train as our host and conductor.