The young worker Helena Pokorná and her widowed father are employed in the same factory. The father is spending his holidays at home in Prague and is looking forward to work. Helena is to go to the seaside for a rewarding holiday. On a hot July day, the girl rides to work in a crowded tram. On the embankment, the crowd pushes her out and Helena fails to get into several other cars. Tempted by the river, the girl calls in sick to work. She takes a steamer to Modřany. There she meets a young man who wants to sleep by the river after his night shift. Helena is drawn into the strange pastimes by a group of notorious loafers and water girls.

It is 1905. The police director gets Jindrich Legenda (Eduard Cupák) shadowed as, yet Legenda had served his sentence for a burglary, the jewels have not been found. Russian revolution encouraged also Czech workers to fight for their rights. Radical anarchists are followed by Legenda's friend Karel Wohryzek (Vladimír Mensík) who was forced to collaborate with the police as he was convicted of pornography distribution.

The year is 1918. Toník returns home from the front. In Kladno, where he arrives, things are seething with discontent. The Social Democrats are in government, but nothing has changed. Socialization has not been implemented, there is hunger and food is still being skimped on. The first news about a socialist state arrives from Russia. On May 1st, the workers' Kladno manifests its loyalty to the ideals of the Great October Socialist Revolution. In December 1920, a general strike is declared in Kladno as well. The workers arm themselves, workers' councils take over the administration of the city and are also established in the surrounding villages. An armed uprising is being prepared. However, the right-wing leadership of the Social Democratic Party attacks the workers in the back. The army is sent to Kladno...

A new teacher with high standards and a strong sense of duty replaces an easy grader. Once bad grades begin to pile up, a product of his predecessor's subservience to the system, the new teacher has to stand up for himself and his students.