Souta Hosono is a hikikomori, an antisocial boy who spends his school time in the infirmary. He becomes infatuated with a classmate, Kiwako Nitta, stalking her and her boyfriend, Hirohisa Sugita. One day, Souta overhears Hirohisa telling his friend, Sawazaki, that he will "lend" Kiwako to him so that Sawazaki can lose his virginity by raping her...