In feudal Japan, magic is dying. As a demon hunter, Akakiba finds this problematic. The evil he's been trained to destroy is disappearing and, along with it, the shape-shifting abilities of the clan he left behind. With his only companion, a determined young human named Yuki, Akakiba traverses the country slaying demons and performing odd jobs.

But when an army of demon-possessed humans masses to exterminate his clan, Akakiba must put aside old feuds and protect his family–all while hiding an important secret from Yuki. Will they find a way to defeat the demon possessed before it's too late? With magic dwindling, will it matter either way?