After the events of the TV series, the 18 year old Yoko Godai has abandoned her special agent Saki Asamiya name to return to her normal life, and is now studying for college entrance exams. However, she accidentally bumps into a young man named Kazuo Hagiwara trying to escape from a group of hitmen, and learns that he comes from Sanko Academy, a private school located in a remote island known as Hell's Castle. The school is ruled by a former revolutionary thought to be dead named Hattori who is trying to brainwash students into terrorists to help him stage a fascist coup d'etat in Japan.

A boy seeks manhood in joining his school’s militaristic cheer squad.

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.