A girl shouts "penis" while running through the train station. In that instant, I fall flat on my face.

After the enactment of the Public Morality and Wholesome Upbringing Law sixteen years ago, all sexual words have been lost in Japan. Okuma Tanukichi has entered one of the few schools with excellent public morals where his beloved upperclassman Anna serves as student council president. However, an obscene terrorist going by the name Blue Snowfield blackmails him into joining SOX, an obscene terrorist organization! Is this a prison or is it a harem?