The kingdom of Atlastia --

North of the world, there's a group of flying islands - this is where the flying continent of Atlastia and its well-known titular kingdom is located. And not only in Atlastia itself - everywhere across the flying islands - the legend of a particular clan is being passed down from generation to generation.

The legendary heroes clan, "Oasis."

Even though they had saved the continent 100 years ago, their sub-commander Chester Silver has laid dormant for ages now. Now, about 100 years have passed and as Chester wakes up from his long arduous slumber he...

...bears witness to the Idol Princess Claria singing her songs to entertain the public. He wakes up as being one of her supporters cheering her on.

And then --

Spurred on by Claria's admiration for the Heroes Clan "Oasis," Chester Silver gathers his former companions, the twin sisters Angelique and Juliet Gilbert, to embark on a new adventure.

At the same time, a mysterious woman who had woken up from her slumber in the crypt of a ruin, Colette says:

"Now that Colette has woken up, this world's fate is sealed."

Strange incidents begin to occur in the world and with the causality of 100 years past intertwining, the adventure Chester seeks is closer than he thinks.