At age six, Rintaro is diagnosed with Henisei Tashu Ijou Syndrome (also known as Hentai Syndrome), a condition that could kill him if he becomes sexually aroused. To save him and allow him to live as normal a life as possible, his father spends ten years in the mountains teaching him to control his body and mind through the martial art of Koei Sougetsu. At sixteen, he decides to enroll in Nangokuren High School, which he assumed was the country's largest all-boys school but is actually its largest all-girls school that has just become co-ed. On his first day, he stumbles upon a large-scale battle and learns that the school's first rule is that it "Abides the Law of Nature," which has turned the campus into a war zone-like environment. Rintaro now views transferring out as his mission, but will it be that easy now that he has caught the eye of the three "Dragons," the bold female leaders of the three biggest factions?