After a string of narcotics investigators disappear, elite agent Nagisa Mitsuki joins the badly understaffed division. Driven by justice and revenge, she recklessly investigates alone, gathering intelligence on the Black Lion Society's Moriyama group before entering its hideout building. A trap awaits her inside. Nagisa is captured, restrained and injected with the very illegal drug her team had been pursuing. What fate awaits the strong-willed investigator?