The widow Rosaria moves to Milano from Lucania with her 4 sons, one of whom is Rocco. The fifth son, Vincenzo, already lives in Milano. In the beginning, the family has a lot of problems, but everyone manages to find something to do. Simone is boxing, Rocco works in a dry cleaners, and Ciro studies. Simone meets Nadia, a prostitute, and they have a stormy affair. Then Rocco, after finishing his military service, begins a relationship with her. A bitter feud ensues between the two brothers, which will lead as far as murder...