The island of the everlasting summer, Seiran Island.

Junnosuke Tachibana, whose family home was on this island, returned to it with his sister, Asane Tachibana, after the death of their parents.

However, Seiran Island has become a place of madness due to the implementation of the "Perverted Law,” a law designed to combat population decline. This law permits and even encourages lewd sex acts everywhere on the island, and refusing to engage in "reproductive activities” is punished almost as severely as a crime.

Junnosuke, a proud virgin and staunch defender of virginity, questions the legitimacy of this law. Determined to protect both his and his beloved sister’s purity, he forms the anti-copulation front NLNS (No Love No Sex) and sets out to destroy the Perveted Law once and for all.

"I’ll… destroy the Perverted Law!”