Drawing close to 300 years after the revival of the world, Morastrum threatens to rise again and the world has been experiencing changes as strange structures have been appearing all over the world. These structures have been simply named as Graves, as they contain the memories and living images of people from other worlds within their halls. While some Graves are seemingly harmless, some have served as bases spawning hordes of monsters and are used to seal evil-natured entities that seek naught but destruction. Word has spread that by reaching the highest level of these towers would allow the recruiting of these warriors, be them of good or ill nature. Zenon Ausbach, current Marquis of Loanne, has been aware of this for quite some time and has decided to intervene by creating the Grave Knights, a task force comprised of select people dedicated to combating the growing menace of the Graves. Meanwhile, the ever growing Messina Empire has sought to claim control over the Graves and its warriors so they could impose their rule over the world by force.

A prophecy spread by an infamous astronomer named Ren Dahao mentions that these events will led to the eventual fight for the fate of the world by seven mighty figures led by their leader who goes by the name of "Polka", their greed for power and fall into a world of tyranny and the sudden apparition of the savior "Starmaiden" and her partner, both fated to thwart the evil ambitions of the corrupted heroes.

What shall be the true fate of the world in the end? And why has Morastrum suddenly returned to the starry skies? Only time has the answers to these questions...