The 10 Rules comedy tells a story of a shy scientist Marek who falls hopelessly in love with a seemingly inaccessible girl. His friends determined to help him, call Marek’s father, a successful publisher of books on the subject of how to get a woman. Together, they begin to develop a very peculiar course on girl psychology. However, do these 10 sure-fire rules apply exactly as described in the books?

The second part begins shortly after the death of Michal Dostál, the biggest bastard of them all. Michal's father and grandfather are convinced that teacher Majer was behind the murders of all three students and was avenging his sister's death. They begin to psychologically torment Majer and search for evidence. The new police investigator Karas, who takes over the case from the deceased police investigator Paleček, is also looking for evidence. Karas immediately suspects something is amiss in the deaths of the "bastards" and also begins to focus on Majer, who is now the school principal.