Players will play the role of an investigator under the "Fog Investigation Team" and are ordered to explore the continent shrouded in thick fog by airship. Players need to lead investigators with different personalities and abilities to fight against visions and monsters from the fog and find out the truth behind the fog.

After a long and lengthy family war, Taimulan has long since entered decline. Nowadays, on this land where the miracles are declining and barren, there is only the last family of "human beings" left to live and multiply alone, mingle and struggle. The story begins with a sudden disaster - the sky-high fog from the North engulfed the Belur Province in the western border of the empire in one day. The pale fog condensed into a sky-high barrier, which also cut and obscured the human homeland. There was no more news from each other. Monsters, visions and nameless killing legions emerged from the strange thick fog, threatening the safety of the last group of dependents. In Belur Province, all forces trapped in the fog jointly formed the "Fog Investigation Team" in order to find out the truth about the mutation. People from various forces have very different customs, technologies, and preferences, but they also put aside their prejudices in the face of crisis and work hard to solve this disaster. "You" with outstanding qualifications also appears at this time. You were invited to become an investigator and ordered to embark on a journey with your companions to find a glimmer of life in the fog... and the truth buried in the earth, oceans, stars and blood.