The reclusive high school student, Hei Jiu, who clandestinely engages in a nefarious profession, suffered a tragic accident during a spring outing organized by his school, resulting in a collective transportation to a world teeming with monstrous beings. It is here that he encounters his sister, whom their parents sold in their youth—a demonic slave named Bai Ling, who is on the brink of ending her own life. “If justice has its noble heroes, then darkness is equally entitled to its savior. Yet, saviors are invariably drawn to cleanliness. Thus, individuals like us, who dwell in the filthy underbelly of society, are destined to remain unseen and unloved by them. Therefore…”