A German engineer arrives in Warsaw. Tonight, he will be with his Polish mistress; tomorrow, at a workers bar in the city’s factory district, where he will meet with Colonel Mercier in a backstreet cafe. Information is be exchanged for money.
Mercier loathes the niceties of Ambassadorial lunches, cocktail parties and banquets of a world not yet at war, but one in which the martial drums can be heard ever more insistently in the background. They take on an altogether more interesting shape when he meets the enigmatic and beautiful Anna Skarbek.
While secretly observing Panzer exercising in the Black Forest, Mercier sees a simple trick performed with a length of pipe strapped across a car and draws his own conclusions about exactly what it is the Nazis are planning.
When the Nazis find out what he’s been doing, his own life becomes their target.