The Osterman Weekend
Robert Ludlum
 John Tanner, the host of an investigative news show, is convinced by a CIA agent that the friends he has invited to a weekend in the country are engaged in a conspiracy, called Omega, that threatens national security. But then everything John Tanner thinks he knows about his closest friends is overturned, and he is set against them. But when Omega finally reveals itself, he realises that he has been manipulated from the very start. The novel was the basis for the film of the same title. fr:Le Week-End Osterman