The third season of the TV show Babylon Berlin features a character named Marie-Louise Seegers, who is the daughter of the fictional Major General Seegers, head of the German Army in the early 1930s. Unsurprisingly, Marie-Louise spends much of her life in the circles of right-wing elites. But there is a twist: she is a dedicated communist and uses this proximity to the ruling class to steal secret documents from her father, which she passes on to left-wing newspapers.

This sounds as implausible as much else in Babylon Berlin. But the character is based on a historical figure whose life was even stranger. Kurt von Hammerstein was the head of Germany’s Supreme Army Command from 1930 to 1934. His daughter Marie Luise was a Marxist who worked for the intelligence service of the Communist Party of Germany (KPD). As the historian Ralf Hoffrogge has observed, her story has been told in multiple novels — but poorly, as an ingenue manipulated by older male communists.

Marie Luise von Hammerstein, called “Butzi” by her family, was an independent revolutionary. She had a short and passionate affair with her fellow law student Werner Scholem, but by that point, Scholem’s ultraleft politics and opposition to Joseph Stalin had led to his expulsion from the leadership of the KPD. Marie Luise developed her connections to the M-Apparat, short for the Military-Political Apparatus (one of many names for the red spy service), entirely independent of any of her romantic entanglements.