"Ijō Chitai Jikken Dorei" is a dark fantasy anime series set in a dystopian world where humanity is plagued by monstrous creatures known as "Hiruko." These beings emerge from a mysterious red mist that engulfs the land, rendering it uninhabitable and forcing survivors to live in isolated, fortified cities. The story centers on a young man named Kufa Vampir, a skilled and enigmatic "Artisan" who serves as a bodyguard and protector. Artisans are individuals with enhanced abilities, created through forbidden experiments, and are bound to serve their masters, often referred to as "Dolls."

Kufa is assigned to protect a noble girl named Melida Angel, who aspires to rise above her station and become a true noble despite her commoner origins. Melida is determined to prove her worth by participating in a deadly competition known as the "Sword Artistry Festival," where participants battle to gain recognition and status. However, the festival is far from a simple contest; it is a brutal and politically charged event that exposes the corruption and cruelty of the ruling class. As Kufa and Melida navigate the treacherous world of nobility, they uncover dark secrets about the origins of the Hiruko, the red mist, and the true purpose of the Artisans.

The narrative explores themes of power, inequality, and the moral ambiguity of survival in a fractured society. Kufa’s past as an experimental subject and his growing bond with Melida add layers of complexity to their relationship, as they struggle to reconcile their roles in a world that exploits and dehumanizes them. The series delves into the psychological and emotional toll of their circumstances, highlighting the tension between duty and personal freedom. As the story progresses, the characters are forced to confront the harsh realities of their world, leading to dramatic confrontations and revelations that challenge their beliefs and loyalties.