Ayazawa Yuki is emotionless student in the morning and assassin at night in order to look for the person who killed her parents. Assassination jobs were given by Tsukimori Touma, who is a teacher in her academy. Everything was normal to Yuki, until a person named Kyouya Hibiki annoys her. Will she start to feel different emotions because of him? Or will she turn her back at him and continue her duties as an assassin?