Atori has an unsual part-time job : she’s a demon hunter! After school, she’s hunting demons for a mysterious organization named N.U.E. To kill her enemies, she unsheathes her sabre hidden in her hair. However, Atori, herself, is half-demon, but she forgot everything about her past. Even though she’s different, she was able to overcome the difficulties and made friends with both humans and demons. Even though her life was calm so far, a terrible shadow now lurks around her...