Le fils de Monsieur Ledoux 105 years old

Gérard, who grew up without parents, has become a doctor and has made an important medical discovery. But he needs substantial funding. One night he finds a brochure about the life of actress Mariette Ducros, now dead, and her child. Her father, Ledoux, lives in Blois. He is a rich collector. Gérard pretends he is Mariette's child. Mr. et Mrs. Ledoux greet him warmly. Out of shame he confesses the truth to Mrs. Ledoux. When she tells her husband, he decides to go to Gérard's office. He talks to Gérard's patients, mothers who claim his medicine saved their children. Mr. Ledoux realizes he found an adopted son in Gérard.