Traumatized by the War of Algeria and by the accidental death of his wife and his son, Manu left the right road. His last caper was the attack of the Antwerp-Tangiers Express, carrying a precious cargo of industrial diamonds. But the whole affair was bungled and all of his accomplices got shot. The only survivor of this disaster, Manu now finds refuge in the mountain house of Lucia, the widow of a smuggler who lives alone there with her little boy.
Free-lance undercover agent Coplan receives a phone call from an old girlfriend in Turkey. The panic-stricken woman gives sketchy details of a plot that threatens world security. When Coplan arrives, he is told the woman has been killed, and the trail of the murderer leads to her mad-scientist brother.
