The super popular work by the highly acclaimed author Esa x Fitch, which has sold over 270,000 copies, is being adapted into a live-action film starring Konatsu Kashiwagi! Ryuya visits his girlfriend's parents' home to announce their marriage. There, he reunites with Kouka, his younger sister whom he used to take care of when she was little. Unlike the innocent days of old, Ryuuya was seeing Honga again after a long time, and she had grown into a full-fledged adult woman. That night, while the two were enjoying alcohol together, her sister fell asleep early. Seeing this, Honga tempted Ryuuya next to her sister. Ryuya's reason wavered, and despite feeling guilty, he ended up having a physical relationship…
