After the old godfather's death, the family is reduced to a street gang. The cold-hearted elder brother and sister, fighting over the inheritance, force their third sister into marriage to pay off debts—and abandon the "simple-minded younger brother" who has returned after ten years missing.
Little do they know, the brother suffers from a dual personality caused by childhood trauma. Normally childlike, whenever his third sister is in danger, the ruthless "Hades" personality awakens in the dead of night to slaughter their enemies. The third sister severs ties with the family, retreats to a run-down bar, and protects him with her life.
As the brother and sister tighten the screws, the male lead is triggered into personality fusion and quietly recovers—but keeps playing the fool, secretly buying his sister a manor. The crime lord's daughter searches desperately for the homeless boy who once saved her, and recognizing him by a token, insists on marrying him.
At the wedding banquet, the elder brother and sister witness the bosses they once looked up to groveling before the male lead—their worldview shatters. They weep and repent, but are cast out of the family and reduced to vagrants. In the end, the male lead rises as "Hades" to the top of the night empire, finding fulfillment with his third sister and his beloved bride.
