Miho is no longer feeling any excitement from sex with her boyfriend Shigeki. At a secondhand bookstore, she finds a book called "The Secrets of Female Body Development" that claims to turn any woman into a master of her vagina. She immediately tries to put into practice what is written in the book, but...

Jin’s recent life as a gigolo had been going terribly. No matter how long he waited, he couldn't find any good-looking woman. When he did finally find one, she turned out to be in the same business as yakuza and ended up taking his money, and to make things worse, she was into sadomasochism. In the middle of this mess, Jin runs into Ranko, one of his ex-girlfriends and both begin living together again in a strange and unexpected arrangement. Ranko now wants to live a honest life with him, but Jin hasn’t changed at all...