Based on a true story from 1936: Klara Baumann, a working-class woman, communist and mother, flees her German homeland for neighboring Czechoslovakia. When a party courier is arrested in Berlin, Klara agrees to return to Germany with illegal material. On behalf of the central courier service, she returned to Germany illegally many times, risking her life, in constant fear of being caught. When the illegal party cell in a large Berlin factory is arrested, Klara distributes the latest issue of the Red Signal on her own. She wants to prove to the Gestapo that she has imprisoned the wrong people. Authentic story of a communist and mother who flees her German homeland for neighboring Czechoslovakia in 1936.