In Shangai, the "Green Dragon" threatens to kill Herbert Aboody, a rich exporter, unless he pays him 50,000 dollars. One of Aboody's secretaries calls inspector Wens for help. An amazing fact occurs, Wens kills Aboody and then disappears. What is the key to this mystery?

A burglar, Bob Duchemin, is charged with murder following a mysterious settling of accounts. Suspicion also falls on the manager of a cabaret on the Champs-Elysées, as well as the owner of the establishment, Enrico. But Bob is also found guilty and sentenced to twenty years' hard labor. Soon abandoned by his fiancée, Lili, Bob learns that she has become Enrico's mistress, one of the attractions at the Tipico. The young singer's affair quickly makes her an international star. For his part, Bob escapes and seeks revenge. He meets a young pure freak who dissuades him from carrying out his murder plans. Bob kills Enrico anyway, but in self-defense. Afterwards, having been found innocent, he will be able to "remake his life" with the pure young girl.

In Paris, three models are murdered, being one of them the mistress of the fashion designer Dominique Airelle. It is the young inspector who is in charge of the affair.

For the Marquis Barbezieux de Saint-Rosay, nobility is important. If anything can comfort her, it's her family tree. In order to erase any doubt he invites in his castle a cousin of his established in Scotland, whom he instructs to bring him his titles of nobility. A first person introduces himself, calling himself his cousin, but it's not him. Then one, then two, then three false cousins ​​appear in turn. Will the real Saint-Rosay of Scotland eventually present itself?

After a Parisian haute couture house is robbed and jewels stolen, Commissaire Legrand leads the investigation. His suspicions fall on Linda, the great couturier. He decides to follow her to Nice to present her next collection.