The Empire, a nation of advanced machinery and science. The Nebulis royal household agency, a land feared as “the country of wishes.” In the midst of the long, endless war, between the two, the boy and the girl meet.

The ice witch revered as the strongest: Princes Aliceliese
The young swordsman who is among the Empire’s greatest forces: Iska

The two meet as enemies at war.
However, just as the boy is enchanted to the girl’s beauty and nobility, the girl is attracted to the boy’s strength and way of life.
Cooperation is impossible, and there is no path forward except through the other. And yet..

"Why does no one remembers the true world...!"

The era when the great race of the five tribes competing for hegemony on the ground ended with the victory of mankind led by hero Sid. However, that world was suddenly "overwritten" in front of a boy Kai. In the rewritten world, Kai saw the scene where humans lost to the five tribal wars because of the absence of hero Sid—here dragons and demons dominate the ground, and Kai is a forgotten existence from all human beings. However, after encountering the mysterious girl Rinne, Kai decides to break this rewritten destiny. In a world without heroes, he inherits the hero's sword and martial art and challenges the mighty enemy races who reign supreme.

On this world, humans are invaded by the existence called Yuugenshu. People were able to survive because of the floating continent, Obie Crea, protected by Priestesses’ prayers.

Sheltis had once aimed to become a Sen'nenshi—a partner of Yumii, his childhood friend and also a Priestess. However, because he fell from the continent to the Eden <Garden of Corrupted Song>, he harbored Mateki, what only Yuugenshu have, inside his body, and was exiled from Sophia <Tenketsu Palace> where Yumii lives. Meanwhile, Yumii was hoping for Sheltis to become her Sen’nenshi, but because he fell, her wish is still unfulfilled. A multi-layered world fantasy where their feelings intertwine!

Three quarters of the world is the world of the dead. The world has been invaded by phantoms. One day, a boy named Nagi finds in the mountains of scrap wood a mechanical teenage maid girl. He immediately takes her home to repair her. The first things that Elise, this mysterious mechanical maid, says is, "Good morning, Nagi." Who is this mysterious silver haired girl? The fate of the world rests in their hands.

The valuable treasure, the “Encore” which was left by the legendary Brave Hero Elline, has the recording of the end of the world and the reincarnation of the world. The countries and parties all over the world are searching for the location of its whereabouts; the age to fight for the Encore. The boy called Ren who wants to become a MASTERKnight has no talent in wielding swords despite looking exactly like the Brave Hero Elline, he has been having a lifestyle where people taunts him as the “Fake Brave Hero”. The one that appears in front of him is the legendary Dragon-Princess Krische, who had awoken from her seal. She mistook Ren for Elline. Though she gets disappointed since he simply looked like him, she later finds out a hidden potential in him. And she invites him to the journey to find the Encore together with the Archangel Phia and the Demon-Lord Elise that saved the world before. “Do you want to come with us?”