After attending to a suicidal young man, Dr Richard learns that his wife has been unfaithful for years. This comes as a shock after 10 years of supposedly happy marriage. Back home, he demands answers from Madeleine. A long night of explanations ensues.

At the end of the 19th century, during a ball in Joinville, on the outskirts of Paris, Georges, a former delinquent working as a carpenter, meets Marie, a young woman connected to a criminal gang.

Evanella, who writes the “Horoscope” section of a major newspaper, and her brother Méristo, create with the help of a young journalist, Jean Lassère and the capital of their uncle Amédée, a “Bureau des Prédictions”. Success being expected, they manage to obtain revelations about a gang of gangsters which they publish as predictions. It is success and fortune. Jean marries the newspaper director's daughter and Evanella the director himself.

Léontine, an old baroness, opposes her granddaughter's wedding for moral reasons. But Adolphe, her first husband reminds her that her own conduct in the past was far from irreproachable. Didn't she cheat on him ? And after her divorce from him and her remarriage with a baron, didn't she do the same thing to her second husband? Léontine then realizes she is in no position to lecture her granddaughter, all the more as she loves her fiancé truly.