After meeting briefly in Paris and falling instantly in love with Alexander Lowenstein, an American, naive and determined Catherine Bresson defies her father's objections by continuing to write to her American suitor who is insistent in his pledge to return to her. When Alex is manipulated into marriage by his girlfriend, Catherine puts her feelings for him aside and eventually marries Gerard Cremieux, a young Jewish law student from her village in the south of France. Their lives go on separately, Alex as a high school teacher in New York and Catherine as a young wife. When Gerard dies unexpectedly, Catherine, overcome with grief, reaches out to Alex and their long-distance love affair begins again through once-a-year letters until Alex can divorce his wife. When the Nazis invade the south of France, Catherine's life is thrown into turmoil because of the smoldering anti-Semitism there. It is only after the war that pure happenstance reunites her with the man who promised to return to her thirty years before.