Youichi is a serious, stoic young man who has a girlfriend and a regular sex life. However, he has never experienced sexual self-gratification. Recently, he noticed a book titled "Masturbation" at the library where he works—an educated discourse on the history of the sin of Onan and related practices. Finding himself increasingly intrigued by the concepts within, he begins to conduct a series of experiments... Join him as he embarks on a whole new world!