Mafuyu is the no-nonsense, take-charge and hard-hitting leader of her high school gang. But when she gets expelled for being a delinquent, her mother, fed up with her daughter's wayward ways, sends Mafuyu to an isolated school far off in the country.

Someone mysterious is pretending to be Super Bun and harassing the members of the student council! Mafuyu and friends almost capture the impostor, but she manages to give them the slip. Then a chance conversation with Okegawa gives Mafuyu just the clue she needs. Has she finally worked out the identity of the fraudulent Bun?!