In the Edo period, there was a shrine maiden called "Itsukihime" in the mountain village of Kadono. Jinta, a young man who acts as the shrine maiden's guardian despite being a stranger, encounters a mysterious demon who speaks of the far future in the forest where he went to defeat it. From Edo to the Heisei era, this huge Japanese fantasy series follows a demon man who travels through time while continuously questioning the meaning of wielding a sword.

Kaname Aizawa and Shiina Hinami are classmates, one day the two bumped into each other, breaking Kaname's glasses and scattering Shiina's belongings. Kaname helped her and accidentally opens her secret notebook, attraction begins between them.