Bernard, a successful Parisian architect, juggles three flight attendant fiancées: an American woman, a French woman and a German woman. He tracks their airlines' timetables, and his long-suffering housekeeper, Bertha, reluctantly resets the menus and bedroom decor depending on the arrivals and departures. Bernard has been successful at convincing each woman that she is the only one.

Bernard's old school friend Robert arrives unexpectedly, and Bernard proudly explains to his wide-eyed visitor how he makes his busy romantic schedule run smoothly. He also has a fallback plan for keeping his fiancées separate, involving his country house. Unfortunately for Bernard, a new, faster Boeing jet has been introduced, changing the timetable. Weather delays occur, and complications arise when the women's behaviour does not match Bernard's careful planning. Robert steps in to help Bernard by keeping one or more of the women busy as they arrive ahead of (or behind) schedule. It becomes more and more difficult for Bernard, Bertha and Robert to keep the women separate once they all arrive, and the lies told become more and more difficult to reconcile. Bertha is exhausted and threatens to quit.