The film recounts the life of a young member of parliament who joins the Freemasons in order to relaunch his career. He thus learns of how the Freemasons are conspiring with the Jews and the Anglo-American nations to encourage France into a war against Germany.

Monsieur Durand-Bidon's mother-in-law is decidedly cantankerous. She never ceases - she who is a duchess - to reproach the latter for his low origins. One morning, at dawn, while he comes home "well watered", he is surprised with a comrade at the bottom of a bathtub. Taken for a homosexual, overwhelmed by Step-Mom, he will never stop trying to escape her and will end up, after many adventures, by learning a somewhat embarrassing secret about the pseudo-nobility of his step-family.

A prestigious Paris doctor is tempted by a woman he knew in his youth, whose politician husband has neglected her.But will he in turn neglect his duties toward work and family?