Professor Mamlock, a successful and respected Jewish surgeon, does his best to ignore the political crisis of the Weimar Republic. He is greatly troubled by the political tendencies of his son, Rolf, a passionate communist who is determined to resist the strengthening Nazi Party by all means. When the Nazis seize power and brutally crush all opposition, Mamlock is forced to leave his clinic for Jews are no longer allowed to practice medicine. He is dragged through the streets by SA men who emblazon his doctor's robe with the word "Jew". Mamlock, broken and humiliated, attempts suicide but fails. As he recovers, he hears an SA rally outside the hospital. He carries a speech calling on the people to resist, having finally realized that his political apathy was a mistake. The SA shoot him dead. Rolf, who escaped a deportation to a concentration camp, becomes leader of a new resistance movement.