Grey contre X

In India, a British detachment finds itself surrounded in a village by invisible enemies. An officer is assassinated, then another. The adversary seems very well informed. By who ? A group of twenty men who had gone to seek help were annihilated. An American reporter will force the mysterious spy to denounce himself.

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.