American Grace Allingham (Deborah Kerr) marries Frenchman Charles Edouard de Valhubert (Rossano Brazzi), but their marriage quickly becomes unusual. Because Charles cheats on her and lives away from his family out of professional obligation to his government, Grace ends up raising the couple's son, Sigismond (Martin Stephens), on her own. Grace and Charles are finally reunited after nearly a decade apart, and, while they seem headed for a permanent split, there's still a spark between them.