With the help of his assistant Anja, Ottocaro Weiss intends to put the plague on stage: circumstances beyond his control and a lack of fresh talent have forced him to close down his flea circus. For Weiss, the plague means the «extinction of everything that makes life miserable and low and freedom along with it. Unbeknownst to him, he has won the support of a patron who is of the exact opposite opinion: for Johannes Wagner, the plague is an organising principle, and, aided by his agent Moosbrugger, he is able to smuggle a new number onto the programme. Whereas Ottocaro Weiss means to represent the plague theatrically, what appears on stage is the scientific reality of the rat-borne infestation.

The young unskilled worker Günter is employed in a foundry and spends his free time with friends of the same age. Together they form a motorcycle gang. But then Günter meets the daughter of an authorized signatory, Gisela, whose parents do not take kindly to the allegedly indecent young man. Gisela takes flight and introduces Günter to her parents on the spur of the moment so that they can overcome their prejudices. But it comes to a violent quarrel between Gisela's father and Günter...