With the addition of Kaori into their party, Hajime and his friends make for the coastal city of Erisen. While crossing the Gruen Desert, they meet a young man on the hunt for a cure to a mysterious disease that has struck his people. A mineral known as stillrock holds the key to saving his country, but it can only be found inside the Grand Gruen volcano. Hajime agrees to help him procure some, and the party begins their quest to conquer yet another labyrinth. But along the way, they meet the most unexpected foe...