Kojuurou is a normal office worker, but when his grandparents from his father's side, who raised him after his father died, call him to visit them in their remote village, he learns that there is more to him than he thought. As it turns out, his family are the heads of a shinobi clan whose history can be traced to the warring states era. Furthemore, the birth rate of males in the clan is incredibly low, meaning he is the only male other than his grandfather and technically the chief. Therefore, it falls upon him to impregnate all the hot and thirsty kunoichi of the village and ensure the legacy of the clan is carried on by having having a male heir.