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.
Kouhei Aizawa is a freelance cameraman who moves from Tokyo to Karuizawa with his roommate. He starts dating Kaoru, his roommate's sister as well as Noriko, the female head of a bosozoku.
Following in the footsteps of manga such as Doraemon and Obake no Q-Taro in that the alien Ganmo (who resembles a chicken wearing sneakers) sets out to help his adopted human friend Hanpeita.
