Kugaya is a teenager who lives with his aunt, Sakuri.

The kendo coach at his high school, Narugami, has been after him to join the kendo team; but when he meets the new girl, Takemi, his life takes a supernatural turn and he is thrust into an epic battle with the demonic "Intruders".

Reincarnation... buried memories... the Holy Sword... "Himuka"... and the Clan of the Swordsmen... it's all too much for a high school student to bear!