Centuries ago, vicious and bloodthirsty demons who were immune to all manner of weaponry plagued mankind. Humanity's cries for help brought forth the Idaten; battle deities who would use their incredible speed to hunt the demons down, and then seal them away. In the following 800 years of peace, the Idaten have not had any enemies to fight. But that is about to change...

Miku suddenly appears in public and quickly the Idatens go after her to try and capture her, but something is wrong. Why would she appear in public right now?