Erina, a female college student. It's late at night, and she's walking with Shunsuke, a fellow member of their art club. At first glance, they seem like such a perfect couple that you'd assume they're dating—until Shunsuke bursts into laughter and strongly denies it: "We're not!" The art club members are nothing like they appear on the surface. While chatting casually as friends, Erina gradually becomes aroused and erect. Yet she insists, "I'm not!" Unable to endure the friction through her clothes any longer, she finally confesses, "It's inside!" Hearing this, Shunsuke, lost in passion, keeps thrusting and moans, "It's not inside!" Between the two, an unexpected and intense chemistry suddenly ignites.