Shinku is a compelling drama that focuses on the strange relationship that develops between two people who find their lives irrevocably changed as a result of a horrible multiple homicide. The first person traumatized is the lone survivor of the terrible family bloodbath, a girl who grows up to be a pretty college student. The second person affected by this heinous crime is the daughter of the murderer, a young girl who ends up becoming a tattooed bartender. A full decade after the crime, the killer is finally going to be executed, and the surviving member of the massacre decides to reach out and befriend the murderer's daughter. A tentative, odd sort of friendship blossoms between these two people, both of whom seem to have little in common personally, and every reason in the world for not wanting to meet. Yet they do, but not without reservations. And really, is this friendship quite what it seems? Or is it all part of some twisted plan for vengeance?

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.