While Canadian history professor Andrew Stanhope is doing research in Paris on the German invasion of France, his interest is piqued when he stumbles upon an odd exchange of correspondence between Colonel Marius Michel, principal deputy in the Deuxième Bureau, France's counter-intelligence agency, and Louis Chastenet, Directeur général of the Val de Grâce military hospital. The Colonel wants Chastenet to warn the incoming Prime Minister, Philippe Pétain, that there is an active spy in the French war ministry and that Pétain's own ring of advisors includes at least one Nazi sympathizer. In flashbacks to 1940, the story of Marius Michel unfolds as he attempts to track down the traitor, whose passing of military secrets surely contributed to the swift and ignominious defeat of the French by the Germans. Working undercover in occupied Paris, Michel discovers a puzzling connection to the high fashion house Ariège, and its treasonous owner, Louis Loriot. Michel is convinced that the recent deaths of Ariège employees were anything but accidental, and he knows his own life is in peril.