Mayumi Kuroba

At a Japanese school, a desperate student council struggles with a recurring problem. The aggressive and relentless members of the Yagyu biker gang stop by the school each semester to beat up the kids, steal their lunch money and vandalize their belongings. The kids want to fight back but realize they're too weak and undermanned against the bikers, and so they hire a handful of tough gals to train and defend them.

The story revolves around a hardcore Onyanko Club fanatic who decides he wants to kill the girls to prevent the young, cute idols from getting old and married - in a sense, to preserve their youth for eternity.