A light in the sky. A body falling. A kiss. Unimaginable power is awakened, and with it a series of events will unfold that will change Great Japan forever.

Sen must figure out what to do about the "girl who fell from the sky."

With suspicions that his sister is harboring Yukimura, Sen's older brother sends in a spy to discover the truth. Meanwhile, at the dojo, a new enemy appears, and she seems to have a long time grudge on Yukimura...

Sen and Muneakira need answers. A secret operation suddenly turns into a group outing, and in order to infiltrate the Tokugawa database they must both keep it secret form the others. Meanwhile, Yoshihiko's personal assassin has plans of her own, and her job is clear: eliminate Muneakira at all costs!