Gentle Himeko and reserved Chikane were born into very different backgrounds, but still became the best of friends. Their fates, they would soon come to discover, are intertwined in a fashion that they can't possibly imagine -- they are the reincarnations of two priestesses who once sealed the god of darkness Orochi in their past lives. Set to revive again, his giant robot-riding agents have set out to destroy the girls, one of whom is Himeko's friend who is in love with her. Riddled with memories of their past lives, the two try to survive long enough to cast the seal on Orochi again...