In 1916, Europe is engulfed in World War I. On behalf of the German intelligence service, Captain Wedigo von Wedel travels to the Western Front to track down a spy. The spy is suspected to be among the highest circles, as important documents have gone missing and military plans could fall into enemy hands. In light of the Battle of Verdun, intelligence is vital for the Reich, especially since the German agent Mata Hari was arrested shortly before. A chase from Paris to Berlin ultimately leads to a spectacular climax in the battle of the intelligence services.