Reika Washington is a half Japanese and half American girl from California. Her mother is a Japanese woman who works as a fashion designer and her father is an American man who owns a bank. When Reika is dissatisfied with her parents sending her to Japan to live with her grandmother due to a business trip in New York, things get even worst when the teacher puts her in the lowest class in Kunugigaoka Junior High School after she defend a student from the lower class. A lower class known as Class 3-E. But Class 3-E isn't juts your ordinary class, this class also teaches students how to be assassins. WHAT?! Though she's having a rough start in her new school, her day soon takes a turn when Reika finds herself the object of affection by the rebellious and unpredictable troublemaker of Class 3-E, Karma. Karma has a crush on the new girl, but will she reciprocate her feelings?