The film is adapted from Agatha Christie's original novel "Murder on the Orient Express", which tells the story of the great detective Poirot (Kenneth Branagh) who cleverly solved a murder case on the Orient Express. Poirot was awakened three times at night on the Orient Express. The next morning, he found that the American businessman Ratchett (Johnny Depp) who was on the same train was murdered and stabbed 12 times. Poirot made logical reasoning based on the various suspicious signs he observed and the interrogation of the people on the same train, combined with the 12-person jury system implemented in the United States, and successfully uncovered a "collective revenge" case.