Akatsuki; the powerful demon of illness which will spread into the victim, turns their eyes red, and slowly kill them. Usually, they take form of a strong monster connected to the victim's body. The only way to cure the victims infected with Akatsuki is to slash the victim body with special anti-Akatsuki weapons, known as "Crave". The group of people who possess and use these weapons are called as "Kiri-Isha" (Slash Doctor).
Hibiki, the protagonist of this story, is the Kiri-isha. He partnered with Kirisa, another Kiri-Isha. Their mission is to cure people infected with Akatsuki, but what could possibly lies ahead of them?