From Shoujo Yuri Manga Guide:

The main characters are Yajima Junko (Yaji-san) and Shinokita Reiko (Kita-san), two lively high-school girls. They are both very beautiful and very good at fighting with various styles and techniques. They also have a strong sense of justice, and can't stop themselves from helping weak people in need. They are always transferring from one school to another - because every new school they join turns out to be riddled with bad guys (violent gangs, sadistic teachers) and, well, it's always the same thing: by the time they have finished "cleaning up" the place, they have caused so much trouble and angered so many big honchos that they have to leave or be expelled.