Sensational archival discoveries regarding the largest espionage case of the Danube Monarchy. Alfred Redl, an officer of the General Staff and in the service of His Majesty Franz Joseph I, sold sensitive military secrets of the Habsburg Empire to Russia, Italy, and France. With the proceeds from his betrayal, he financed his luxurious and romantic lifestyle. However, Redl's suicide prevented the complete clarification of a scandal of European significance and provided material for myths and legends. One hundred years later, Verena Moritz and Hannes Leidinger embark on an exciting quest for clues: What data changed hands? Was Redl at the head of a hostile network of agents? What were his motives? What impact did his betrayal have on the course of World War I? The two historians bring sensational archival material to life and make one of the most enigmatic chapters of history come alive.