Recruited by a clandestine police organization, "K" must stop a plot by student radicals to create anarchy in Japan. Armed with a hi-tech steel yo-yo, and a new name (Asamiya Saki), she must infiltrate an elite high school to find the terrorists but finds an even more sinister plan is about to unfold.
Teacher Kawashima Haru takes a position on a remote island off the coast of Hokkaido, where she takes charge of six students. However, she is later forced to leave after an accident occurs. 20 years later, Haru learns that one of her former students has committed a crime, and eventually returns to the island once more.
Under the influence of his delinquent friend, a former model student eschews schoolwork and joins a gang of school kids who do nothing but fight.
