天騎士オークに降る。

A demonic force has arisen from below to conquer the human race.
Since human society was exhausted due to the civil war, they were helpless against the evil hordes...
Opposed to the heaven's policy of non-intervention, a legion of celestial world comes down to assist humanity.

While they may have taken female human's appearance, they have godly powers to defeat the demonic forces.
After the war, they became worshiped as the "Three Celestial Knightesses".
But... after a while, these Knightesses abruptly disappear.

This is because the higher beings of the celestial world punished them for their disregard of the nonintervention policy.
It seems like they vanished deep into the darkness of the history...
However, they are still alive. Their dragonic origin protecting them from death, these celestial beings are immortal... Even if they were to wish otherwise...

One of the Three Celestial Knightesses, Hilde, arrives at a village which is being seriously threatened by an army of orcs...