In situations with multiple casualties, a triage system is implemented, utilizing a spectrum of five distinct colors to denote the severity and urgency of each person's injuries. Treatment is then prioritized accordingly. Black signifies th…

Mikami Arashi, a high school student, has successfully removed his first malignant tumor and is now a formal member of the clandestine organization, Black Label. He accepted the role of executioner as a consequence of the events of nine yea…

Kiba Mikoto, a fellow student of Arashi, works alongside him in the organization known as Black Label, battling forces of darkness. Their paths cross with that of Hizaki Chikage, a newcomer to the school, and Mikoto finds himself drawn to t…

Aware of the insidious growth within her, Mikoto departs swiftly and alone to remove it, not pausing for the rest of Black Label. Her path, however, leads her to those experimenting with a novel narcotic, and to an unexpected acquaintance.

A singer, dancer, and actress of exceptional talent, Nashida Oriha is a leading idol and a member of Black Label. She navigates a world steeped in darkness with each passing day. Scheduled to participate in a live broadcast celebrating the …

The curtain was about to rise. Hostile forces had seized control of the television studio, taking the performers captive. A substantial ransom was demanded; failure to meet it would result in the hostages being forcibly removed from the eig…

Sagiri Yuko, Tsurugi Miki, Sayo Hitsugi, Ampule Zero, Arashi Mikoto, and Oriha Ampule One arrived at Tobioka Port to investigate a recently docked cargo ship. Two twins appeared, addressing Hitsugi as "senpai," but their intentions seemed f…

Lost to herself, Hitsuji descends into a destructive frenzy, and her companions from Black Label are forced to confront her. Yet, Arashi hesitates, unable to truly strike her, unwilling to inflict harm. But Yuko resolves to carry out the Tr…

Black Label eradicates the city’s wickedness by cauterizing the festering growths that have taken root within it. Detective Suzue Konomi, investigating the organization, finds herself abducted. The kidnappers' motives remain obscure, and sh…

The Black Label team reviewed their accumulated data, striving to discern the unfolding situation. A new, aggressive malignancy was evident. The meaning of "Triage" for Arashi and the others remained unclear, as did the rationale behind the…