Shiiba-san no Ura no Kao. with Imouto Lip  

椎葉さんのウラの顔. with イモートリップ, 椎葉さんのウラの顔。 with イモートリップ

At a typical Japanese high school, there exist two unique students - a solitary young man and Shiiba, a captivating enigma. Unlike the unremarkable and monotonous boy, Shiiba possesses striking beauty and stands out among her male peers. Despite this, no one has dared to approach her romantically due to her mysterious nature. However, an unexpected turn of events occurs when Shiiba invites the plain boy into a secluded room. On the other hand, in another part of the world, a teenager returns home after a long day at school. As he enters his room, he is startled by the sounds of a pornographic video that he had previously watched. Upon further investigation, he discovers his younger step-sister, Miku, watching the tapes. While it is not surprising to her that teenage boys are drawn to such content, what she does not anticipate is her own fascination with it.