Update: Here’s the story overview from Gematsu:

“Arcadia,” a land dominated by swords and magic. A huge tree from ancient times called “Yggdrasil” exists here and is to be the reason that peace visits the world.

There is a legend about that World Tree. If you can manage to reach its untrodden summit, it is said that your dreams will come true.

“The power to dominate the world.” “The most powerful.” “The world’s mysteries.” “Expensive treasures.”

Although there are four races that live in this land, each has a different legend, but no person has been able to confirm them.

From the city “Aolith” at the bottom of Yggdrasil, the official orders are issued. In pursuit of the legend legend, the courageous adventurers who challenge Yggdrasil will gather in Aolith. And in accordance with official orders, you’ll be the one to gather those adventurers.

Whether it’s for wealth and honor, or to satisfy your sense of adventure, you’ll challenge the labyrinths and aim for the top of the World Tree.