Grey, an elite detective, has the mission to investigate the assassination, in Paris, of a great Hollywood star. There is no real motive, and yet the suspects are numerous. The investigation promises to be long and difficult.

In a small hotel on an English beach, an agent from the Intelligence Service is responsible for finding an important stolen document. At night, a theft of jewelry, including a superb emerald, complicates the investigation. The search for the double culprit proves to be difficult.

A crime has been committed. Two police officers with very different personalities are in charge of the investigation. This one turns out to be complicated, the culprit being almost unsuspected.