At dinner one night, Stan notices that his son, Steve, used communist terminology. He talks to Sergei, who is originally from the Soviet Union and is helping Steve build a model rocket, about Steve's use of communist words and learns of Sergei's plan to "steal" his son. Stan visits Steve in his room and learns that he has become a communist.
1920s Berlin was a city of immense contrasts and inequality. It was in this tumult that communism and Nazism gained adherents. This scene shows a communist protest outside of a police headquarters - these protests were officially banned. The scene ends with some carefree affluent boys talking matter-of-fact about contentious German politics.