In Black Torch, seventeen-year-old Jirou Azuma lives quietly with his grandfather, using his supernatural ability to speak with animals to befriend and protect them. As descendants of a long-standing shinobi clan, both have trained in combat to keep their family's fighting art alive. Jirou's life is upended when he rescues a black cat named Ragou and discovers that the animal is actually a mononoke, a demonic spirit that has long been at war with mankind. When a hostile mononoke comes looking for Ragou, Jirou leaps to the cat's defense, only to suffer a mortal wound.
Rather than devour Jirou's fading energy and restore himself to full power, Ragou gives his remaining energy to the boy instead. The transfer revives Jirou and grants him powerful supernatural abilities that blend with his shinobi fighting style. Their strange bond is witnessed by Ryousuke Shiba, an officer in the Bureau of Espionage whose job is to dispatch aggressive mononoke. Shiba offers Jirou and his grandfather a place in the Bureau's new squad, Black Torch, where they must fight the mononoke that threaten to devour innocent people.
