Siblings Jinta and his sister flee to the mountain village of Kadono during the Edo period, and Jinta grows up to become the swordsman charged with protecting the shrine's priestess. A demon he confronts references events a century and seventy years in the future, and rather than dismiss it, Jinta follows the threat across those years, era by era. The chase becomes as much about confronting his own nature as it is about the demon itself. This light novel is the story's original source.