Aden and Sonja, two lifelong friends, live a quiet life on the island of Fenith until they are haunted by a mysterious curse: they awaken to find that their two souls are now trapped in the same body. To make matters worse, the Fenith they knew has vanished and been replaced by a strange island filled with unknown faces. Only by exploring this new world can they unravel the mystery of the curse and save their beloved island. On their journey, Aden and Sonja are supported by a colorful cast of characters, and they take command of the giant golem Ymir. With the help of their new giant friend, they cross vast seas, discover hidden islands and dungeons full of treasures, and battle terrifying monsters from the depths.