Haramaseya revolves around Terada Akito, a man with “super sperm” capable of impregnating any woman. Akito is hired by a sperm bank to impregnate its clients, with the first being Kumi Iijima, a woman unable to conceive due to her husband’s azoospermia.

It has been three months since Tareda’s first client, who has not become pregnant yet. During their recent meeting, Tareda notices Kumi’s changed attitude towards sex and apologizes for not getting her pregnant. However, the truth is that Kumi now has sex not only for pregnancy but also to feel pleasure.