We all know our blood type, few know the name of the Czech who participated in their discovery. The story of Jan Janský is the subject of an unlikely hero of science, but at the same time it is worth considering the context of the creation of the film. Even at the beginning of the 20th century, doctors did not understand why blood transfusions sometimes helped and sometimes harmed recipients, while the devastating First World War was on the horizon. Through research on the connection between mental health and blood, Janský came to the discovery that there are multiple blood groups. How was the story of a distinguished Czech scientist directed by Martin Frič and portrayed by Vladimír Ráž perceived by the cinematography of the 1950s, which belonged to the sphere of influence of the reigning totalitarian regime? And was she willing to admit that primacy is quite questionable in many scientific discoveries?