After the passing of his father, Rocco Parondi, a member of a struggling rural Italian family, embarks on a journey north from Lucania alongside his widowed mother, Rosaria, and three of his brothers—Simone, Ciro, and Luca. Their destination is the industrial city of Milan, where they plan to stay with their eldest brother, Vincenzo, in the Lambrate suburb. However, they quickly find themselves unwelcome as Ginetta, Vincenzo's fiancée, and her family disapprove of the uneducated and jobless southerners, ultimately relegating the Parondi family to a frigid basement.
Things take a turn when Ginetta becomes pregnant and marries Vincenzo, leaving him with little time for his mother and brothers, who must fend for themselves. Simone, the second brother, struggles with adapting to life in the big city. His infatuation with a prostitute named Nadia leads him down a tumultuous path. Encouraged by both Nadia and their mother, he attempts to make a name for himself in boxing as a shortcut to fame and fortune. However, his romantic feelings for Nadia are unrequited; she ultimately rejects him after returning the stolen jewelry he had given her.
Meanwhile, Rocco, the third brother, is conscripted into military service. Towards the end of his duty, he encounters Nadia following her release from prison, and his genuine kindness emboldens her to abandon her past lifestyle for a meaningful relationship with him. Tragedy strikes when Simone discovers their relationship, unleashing his fury by attacking Rocco and Nadia, resulting in a horrific act of violence as he rapes her, intending to teach Rocco a harsh lesson. Driven by a desire to shield his brother from further pain, Rocco breaks off his relationship with Nadia, persuading her to return to Simone, only to set the stage for her own destructive plans.
Ciro, the second-youngest brother, focuses on his education by attending night school and secures a steady job at the Alfa Romeo factory, striving to uplift his family's stature in their new environment. His dedication leads him to become engaged to a local woman from a respectable background.
Throughout their challenges, Rocco frequently puts his family’s needs above his own happiness. He covers for Simone repeatedly, even retrieving stolen jewelry from Rocco's employer, and eventually, when Simone's boxing aspirations crumble under the weight of alcoholism and self-destruction, Rocco sacrifices his own future. He accepts a daunting ten-year boxing contract to settle Simone's debts, including those owed to a dangerous man he robbed.
As Rocco enters a championship fight, a heart-wrenching climax unfolds. Simone, reeling from the fallout of his violent actions, confronts Nadia near the Ponte della Ghisolfa, where their encounter ends in her tragic murder after a heated exchange. Rocco triumphs in the ring but finds himself shattered, wishing to return home to Lucania as his mother expresses her longing for the family to be united once more. The celebration is abruptly shattered when a bloodied Simone arrives, confessing to the horrific crime. Rocco, despite the turmoil in his heart, wants to shield Simone from the consequences, but Ciro's moral compass leads him to inform the authorities.
Luca, the youngest brother, often remains a passive observer of these devastating events. When he reaches out to Ciro at work, sharing news of Simone’s downfall and his desire to return to the south with Rocco, Ciro expresses doubt about Rocco’s future there. Luca contemplates the changes brought by time, as Ciro looks ahead with hope for a better life, believing that transformation can lead to new opportunities. As Luca departs, he stumbles upon a newspaper featuring Rocco's photo, signaling his rising fame and the unfolding of their family’s complex legacy in an ever-evolving world.
