Akari, working as a corporate secretary, finds her life shattered when her younger brother Shinji offends a yakuza woman, leading to both of them being kidnapped. To atone for her brother's actions, Akari is forcibly subdued by the gangsters and subjected to repeated sexual assaults, gradually descending into a sex slave. Witnessing his own sister's degradation, Shinji becomes intensely aroused, eventually joining the criminal underworld himself and participating in new acts of abuse upon her body. Betrayed by her own brother, Akari slowly loses all hope of survival.