Exotic, pre-war Europe. Margaret Lockwood is the upper class damsel who will soon be in distress. Michael Redgrave (The Quiet American (1958)), because Errol Flynn was unavailable? They meet sorta-cute and the rest is either irrelevant to the ending (they're getting married!) or they are mostly irrelevant to the plot. Director Alfred Hitchcock did not seem to have enough faith in the script (by Sidney Gilliat and Frank Launder, based on the story The Wheel Spins by Ethel Lina White) to let us in on what was going on until my interest lapsed. There's some saucy dialogue of the "preview of coming attractions" kind between a mostly-auxiliary couple on the train.