The Lady Vanishes(1979)

Had she vanished into thin air...Or was she never really there?

On the eve of World War II, zany heiress Amanda Kelly travels by train to Switzerland. While passing through Germany, she meets a sweet elderly lady, who suddenly vanishes. Distraught, she questions her fellow passengers who claim that the woman was never there. Unsure if it's all in her mind or if there's a more sinister plot afoot, Amanda teams up with photographer Robert Condon to discover the truth.