While gaining popularity as an underground idol, Akane Yamamura is lured to an abandoned ruin under mysterious orders. Inside a creepy derelict tunnel, she's told she cannot leave unless she completes a series of assigned missions. She faces harsh trials including remote-controlled humiliating anal inspections and being used as a human toilet for urine. At the request of her passionate fans, she endures face-sitting while singing her signature song. Stimulated anally, she defecates and smears her own feces over her body in ecstatic arousal. After being thoroughly emptied by enemas, she's driven into climax through intense anal sex. This work unfolds a creepy yet erotic narrative, centered around the theme of anal survival.