A heart-wrenching, explicit video left behind on a college student's phone by a member of a romance film club. Office worker Mariko and her neighbor, a university student, secretly harbored feelings for each other but never confessed. Both still young and filled with desire, the student gradually deepened their relationship—touching Mariko's breasts and caressing her over her underwear inside her apartment. One day, a male cousin from out of town visits Mariko, and her behavior suddenly changes. When the student asks, "Has something changed?" she evades the question. Later, the student brings over the latest volume of a manga Mariko wanted to read, but the cousin appears in just a T-shirt and underwear, snatches the manga saying, "I love this series too," and disappears into the back room. Worried, the student returns to return a borrowed container, only to hear strange noises from inside. Mariko seems sexier, growing closer to her cousin. "Did something happen?" he asks. "It's nothing," she replies. Consumed by suspicion, the student uses a selfie stick to secretly record from the balcony—and captures Mariko having sex with her cousin. She moans with an ahegao expression as he vigorously thrusts into her from behind in missionary position. Completely submissive, the shocking sight leaves the student whispering in disbelief, "No way... Mariko..." Stunned, he steels himself, circles around to the front door, and attempts to burst in—only to find... the front door already open...