Kuroki Maya is a handywoman who operates in the shadows. Known as a dark demon hunter, she resolves cases involving spirits and supernatural phenomena. Her true form is that of a witch, and when battling monsters, she arms herself as "Dark Jeanne," using magic to destroy her foes. However, one day a monster named Vain appears—feeding on human desires. This creature possesses greedy humans and attacks Dark Jeanne. Her ultimate magical technique, "Eternal Flame," which has incinerated countless monsters in the past, proves ineffective against Vain. The reason is that Vain-possessed individuals, upon touching the witch Dark Jeanne's body, gain the special ability to torment her groin. This story portrays the battle between the dark world and the witch, as well as the darkness within desire-driven humans.