Without realizing it, Koto locks up Amaterasu, the Sun Goddess, in an unfamiliar domain, leaving her stranded with no means of escape. In her travels through this strange land, she meets priestesses fighting against the spreading malevolence. The priestesses disclose that Black Towers imprison Amaterasu, guarded by malevolent creatures. To set the world right, Koto is required to unite with her newly-found allies to conquer these beasts.