During the Great War, American Frederic Henry, an architect by trade, is in military service as an ambulance driver for the Italians, he driving between the front and the military hospital. His best friend in the war is Captain Rinaldi, a physician with the Italian military. While Rinaldi sees Frederic as his partner in crime in pursuing the opposite sex, Rinaldi is, on Frederic's latest trip to the hospital, already pursuing British nurse Catherine Barkley. In meeting Catherine himself, Frederic too falls in love with her, the feeling mutual. Over the course of the war, Frederic and Catherine face one obstacle after another in being together in what is their true love, those obstacles including the war, Rinaldi, who despite being Frederic's friend, sees Catherine as being nothing but a distraction to him, and real life regardless of the war.