Seirantou, an isolated island in everlasting summer. Junnosuke Tachibana, whose birthplace is on the island, returns to the island with his younger sister, Masane Tachibana, after the death of their parents. However, Seirando is an island of madness, where, according to the “Doskoe” ordinance, which was enacted to stop the decline in the island's population, ‘Dosukebe’ sex is permitted and encouraged everywhere on the island, and refusal to engage in "productive intercourse” is punishable by a crime. Junnosuke, a proud virgin and a virgin's kitchen, has doubts about this ordinance, and in order to protect the purity of himself and his beloved sister, he starts an anti-mating force, NLNS (No Love No Sex), and begins to work to destroy the slutty ordinance--! I'll... I'm going to destroy the Dosukebe ordinance!"