The hamlet of Ootsuka, where Shino Inuzuka, Sousuke Inukawa and Hamaji lived, was set aflame on the assumption that a plague had wiped out every living thing. Surrounded by fire and teetering on the brink of annihilation, the three were approached by a mysterious man wielding a sword. He warned them that survival required a choice, and that night altered the course of their lives.
Five years later, the siblings reside under the watchful eye of a modest Imperial Church in a nearby village. All seems tranquil until the Church attempts to reclaim Murasame"s demonic blade. To accomplish this, they abduct Hamaji to lure Shino—now the bearer of Murasame"s spirit—and Sousuke, who can transform into a dog. The brothers must set aside their differences to rescue their sister from the Church in the Imperial Capital, heralding a perilous journey.