The Gokumon clan is a bloodline said to have emerged from hell, and in the ancient city of Kyoto, a place thick with monsters and curses, they are feared by sorcerers and supernatural beings alike. Nadeshiko Gokumon, a young descendant of this house, was saved from a cremation fire as an infant and raised to fulfill a grim destiny: she must devour monsters. Beautiful and inauspicious in equal measure, she carries the body of an oni yet longs for a human heart. Her isolated existence changes when she meets Amana Ichijiku, a woman who is strange, mysterious, and utterly unafraid of her. Amana, who appears human but harbors a warped soul within her body, becomes Nadeshiko's partner in confronting a series of eerie phenomena. Together they face an entity lurking in a painted ceiling, boxes used for human sacrifice, a curse coiled around a school, a beast that deceives the eyes, and a formless ghost. As the two work through these cases, they are forced to confront the parts of themselves they have tried to ignore. Nadeshiko, who has always believed she would remain a monster, begins to change through her connection with Amana. Their bond gradually cuts open a bloody story tied to their origins, drawing them deeper into a narrative of fate, identity, and the line between human and demon.