It is 1962 and MI6 are covertly monitoring top-secret communications between Washington and Paris. Owing to intelligence passed on by a Russian defector, President Kennedy warns de Gaulle that the French government has been deeply penetrated by undercover Soviet agents. The potential rift between the West's two most powerful allies could split NATO during a time of growing Soviet threat. Faced with the danger of Britain becoming a pawn sacrifice in a nuclear exchange, William Catesby is dispatched to America to report on what is happening - and, if necessary, to take covert action.