It's 1937, and Colonel Jean-Francois Mercier, a highly decorated soldier from the First World War, is the French military attaché stationed in Warsaw, Poland while the shadow of Hitler’s Nazi regime looms over mainland Europe. With intelligence from a German informant, Mercier sets out on a stealth mission with his trusted accomplice Marek, where they discover that the Nazis are ensuring any future invasion of Poland can take place effectively and with little resistance. Amid the threat of a second world war, Mercier finds himself entranced by Anna, a beautiful Parisian lawyer.

Mercier’s mission becomes all too dangerous as his cover is compromised while trying to unearth German military plans, and a man believed dead reappears, sparking significant repercussions for both Mercier and Anna. Will Mercier discover the truth in time, and what consequences will this have on the rest of Europe?