Modern Japan is overrun by "vampires" who mimic and eat people. In order to hunt them down, there are girls who fight in secret with silver weapons in their hands! Among the vampire exterminators, there is a unit of "troublemakers," a.k.a. "Mazarasou." Newly assigned there is Reo, a girl with a certain secret. She meets a woman named Kaika Kiriya, who is one of the most "dangerous" women in the group. A painful, extreme, and sometimes friendship. Hunting, hunting, hunting!