On a lonely dirt road, a car gives up the ghost. Further desperate attempts to start it also fail. After several days, the car becomes a prison for its driver and the situation takes on traumatic forms.
Thomas offers Dorette a trip to Moselle that she rejects saying it's short notice, but when Thomas shows at her apartment the next day he finds she's not slept on her bed. He leaves for Dorette alone, and there he meets Angela.
Observing staunch moral attitudes, professor Traugott Nägler, his wife Marianne, and their swarm of children life a happy and idyllic life in a small town. But when their oldest daughter Atlanta inherits a house in Montevideo that belonged to the deceased sister of the professor, the family′s life is about to change dramatically.
In the face of two world wars, Professor Prätorius, a philanthropist and a surgeon, wants to exterminate the one danger to mankind, the microbe of stupidity, as he states in a spontaneous lecture to his male and female students. When he tries to help a pregnant girl he gets involved more and more in her life and is forced to marry her.