Strange things happen in the overnight express: according to a cryptic, obviously military announcement, the train's telephone link with the outside world has been cut off, access to the rear part of the train has been barred, the windows cannot be opened and the train does not stop at any station. While the train's secretary decides to get to the bottom of these ominous events, the other passengers react quietly and are annoyed by the young woman's anxiety. A young priest prevents her from pulling the emergency brake.