Season 4 of the international hit series Babylon Berlin is set in 1930s Germany, just after the global stock market crash and the Great Depression, and with the Nazis' march to power in full swing. The story centers on detective Gereon Rath and his ambitious colleague Charlotte Ritter. As Gereon's investigations lead him into the fixed fights of the boxing world and politically, uncomfortably close to Hitler's militant supporters Charlotte risks her job to help her homeless sister, who roams the streets of Berlin with a group of young peers, fighting for survival.