Vienna 1934. Ten-year-old Meret Voytek becomes a pupil of esteemed musician professor Viktor Rosen, a Jew in exile from Germany. Three years later, aware that the Nazis are advancing, Rosen tells his promising pupil that he must leave Vienna for London. When Vienna quietly comes under Nazi rule, Meret witnesses the repercussions for the city's Jews, but when her orchestra becomes a division of the Hitler Youth, she complies and wears the uniform. Meanwhile, across Europe, Dr. Karel Szabo, a Hungarian physicist, has been interned in a camp on the Isle of Man. Shortly thereafter, Szabo is transported to Canada and rescued by the Americans, who recruit him to join the team in New Mexico building an atomic bomb.