The Advent of the Priestess of the Godless Month! Shy, timid Himeko happily attends school with both the popular and beautiful Chikane and her childhood friend, Souma, blissfully unaware of what's in store for her. However, the destiny of these three changes on Himeko's 16th birthday when the mark of the sun appears on her chest. What does this solar mark represent? At the same time, why has a black aura of agony burst forth from Souma? Who is the enemy? The legend of the eight-headed beast returns to Japan!

Confronted with his real brother, Souma fights for Himeko, the one he loves. However, if Souma is destined to be the one for Himeko, where does that leave Chikane? Her feelings are so deep and powerful that no one in the world could possibly match the intensity of her love. Chikane is determined to make sure that everyone understands this, including the Orochi, Souma, and most of all, Himeko herself.

In the timeless battle of good and evil, can love triumph? Shy Himeko adores Chikane, the gorgeous and cool "princess" of their exclusive boarding school. She's been looking forward to their joint 16th birthday party for weeks. But on that fateful day a shrine appears in the sky, giant robots ravage the school, and Himeko discovers that she is the reincarnation of the Solar Priestess. As dark secrets unravel, one thing is clear: their lives will never be the same...

Pretty and popular Chikane has two secrets: one, she's the reincarnation of the Lunar Priestess, and two, she's in love with shy Himeko, a girl at her school who's the reincarnation of the Solar Priestess. Will these two celestial bodies finally have the chance to become one, or will fate, jealousy and giant robots conspire to keep them apart?