The story is about Seiichi Ozaki, a private school teacher cursed with a very large penis and tremendous sexual potency.
Ozaki was transferred to an almost deserted island to teach, but in reality, he was sent there to impregnate the local women.
This isolated island has a unique custom where the inhabitants have been selectively breeding the best women for generations to ensure a high birth rate. As a result, the new generations of women are exceptionally beautiful and curvaceous, with a shortened gestation period of only seven weeks.
Despite practicing this custom for the benefit of their ethnic group for many years, the inhabitants’ endogamous practice is now counterproductive. With very few people on the island, the genetics of each individual are too similar, which is detrimental to their survival. This is where Ozaki comes in, a young man who must spread his genes throughout the island by fathering a new generation.