1948. Madeleine is the headmistress of a kindergarten in Ménilmontant. Dr Libois, the school doctor, is very close to her heart. When Rose, a new helper comes to the school, Libois is impressed at once by her understanding of the little ones and her dedication to them. Little by little, Libois grows fond of Rose while becoming estranged from Madeleine. He eventually marries Rose.

An American agent disappears after a scuba diving reconnaissance mission in Corsica. The Secret Service sends agent code name OSS 117 to investigate.

Lucien Bonnet, Jean Vigneron's manservant, blackmails his boss, who is having an affair with Inès de Montalban, married to Ricardo. Vigneron pays the sum but Lucien is killed by an accomplice, Baruch. Everything seems to accuse Jean who, for fear of compromising Inès, prefers to keep mum. Fortunately, his innocence will be proved thanks to a surprise witness. The two lovers flee to Congo while the husband soon forgets them, finding comfort in debauchery.