Tonoda and Hachioji are best friends since high school and live together. One day, Hachioji's girlfriend mocks their male friendship, saying, "No matter how close you are, you can't have sex with your best friend," which leads to their breakup. That night, a drunk Tonoda is persuaded by Hachioji, who asks, "If it's no different from masturbation, want to try it?", and they end up having sex on impulse...!? We are in love now--

A "Free Love Research Club" where even "capturing another persons lover" is allowed - The unpopular student Haruto Sudou is a new member of this club and already taken in by Kaiouji, who's called "the Satan of the World of Dating Paries".