Country doctor Robert Koch is desperate: a tuberculosis epidemic is spreading throughout the children in his jurisdiction – no end in sight, unless someone intervenes. Every fourth child is already sick, the parents helpless but to look on as their children die. Now Koch takes it upon himself, having worked for many years to find the cause of the disease. Further complicating his labors are nay-saying adversaries – one of whom is a teacher who feels he has been dishonored by Koch. But his greatest hindrance is the celebrated Berlin scientist and Reichstag delegate/private counselor Rudolf Virchow: he has the utmost of skepticism for Koch′s theory that a bug is the catalyst of tuberculosis. When Koch′s theory is successfully refined, he is called to Berlin to deepen his research – undisturbed and with all means necessary. But he soon realizes that even in Berlin, not everyone is on his side …