Three years ago, in order to save his childhood friend and unrequited love Yoshino Yuki, a high school student named Mitsuishi Reiya became a nocturnal being who attacks people and slurps their blood. , he meets boys who live in the darkness of the night, hiding the fact that they are nocturnal. In order to escape the violence of night hunting, hide from the public eye, and fight back against their bloodlust without attacking others, they gather at a live house, form a band called 404 not found, and become passionate about music. Each of the members has a history of traveling at night under harsh conditions, and the members sing with a sense of force, expressing their feelings of having nowhere to go in their music. Reiya, who has become a member of such a band, is relentlessly targeted by Kurose Takumi, the leader of the night hunters who hate night hunting.