Hiiragi Kyoichiro, the eldest son of a wealthy family, has left behind his home in Momoki Village to attend the prestigious Imperial University in Tokyo. He carries with him his family's heirloom katana as well as a rather disturbing secret: he can see the spirits of the dead. Even so, he remains optomistic of the future that lies ahead, musing on how less scary the spirits would be if only they were less frightening in appearance. When he awakes, he realizes that he may have gotten his half-hearted wish..in part as he finds he's the one that has become significantly smaller and decidely cuter. As if that's not enough to throw his world into chaos, Kyoichiro soon finds himself swept up into a supernatural dispute between factions of the Imperial Japanese Army intent on creating an army of undead soldiers, a mysterious stranger with vague intentions, and a seemingly anti-government group known as the Five Katana.