Ura Jutaijima is an erotic hentai series set on a deserted island where a deadly virus afflicts the survivors, predominantly young women, by causing intense sexual arousal that becomes fatal unless cured by ingesting semen. Stranded after a shipwreck, the only male among them, a bullied student, becomes their reluctant savior as the girls depend on him for survival, leading to complex and tense interactions as they struggle to cope with the virus and their new dynamics.