During the French Revolution in 1793, a member of the Convention, seduced by the Comtesse de Beaulieu, helps her to discover the truth about the relationship between Agnès de Fitz-James and the count who was guillotined.

The son of a ruined family transforms into a castellan following an inheritance, becomes a parachutist champion in spite of himself, and becomes famous.

Famous singer, René Sartène, falls in love with a young bourgeois, Marie. Irène, her stage partner and the director of the show combine their efforts to annihilate this budding happiness.

1895. Discovery of X-rays. Researchers and scholars are true martyrs, because they do not know how to protect themselves against radiation dermatitis. Professor Belcour has to have one hand amputated, his assistant Henri Vermont, aware of the danger, has the courage to break up with his fiancée. Withdrawn to the countryside, they eventually recover.

In Central Europe, an organization of counterfeiters is headed by Burcq. An Air France pilot introduces an intelligence agent to the principality. A woman, Helene, betrays them first, then in love with Francois, the pilot, helps the two friends to escape.

A historian seeks to clarify the mysterious death of Sire de Malvaleix and will find himself involved in the murder of the current descendant.