World-famous geneticist Professor Hülsenbeck (Norbert Christian) is a man of integrity who refuses to mix science and political gain. Because his findings are being used to harm humanity, he imigrates to the United States in 1933 in protest against Nazi racial politics. But there too, he finds his research being misused against his will.

After WWII, he returns to the GDR to work as a biologist. Once again, the renowned expert faces a inner conflict when state secretary Dr. Brock (Armin Mueller-Stahl) tries to convince him that he is needed for a new human genetics project.