When his widowed father M. Bread (Jean Rochefort) hires Mme Vernet (Dominique Blanc) to be his governess to look after him, and she brings along her son (who is the same age) to provide him with a playmate. Thomas (Regis Arpin) is not amused. After all, he muses, Je suis le seigneur de chateau (I'm the king of the castle). The two youngsters declare war on each other, and the battle rages on while the lads' parents grow increasingly fond of each other. Meanwhile, the governess's husband has been reported to be missing in action in the French-Indochinese War, to the distress of her son Charles (David Behar).
~ Clarke Fountain, All Movie Guide