"The most incompetent person in the world ". Kai Heinemann received this gift at the age of 13. The effects of the gift resulted in Kai's significantly reduced physical abilities, and he became despised and bullied in the gifted supremacy of Lamour.

Kai is forced to leave his home and is attacked on his way to the royal capital, and while desperately running away, he wanders into a dungeon. In the dungeon, he had to clear the "Trial of the Gods" to get out, and the time did not progress.

Kai, feeling like he was going to die, spent 100,000 years clearing the dungeon. In the process of clearing the trial of the gods, Kai becomes the most powerful being in the world, gaining unique and strong friends along the way. An exhilarating muso fantasy by a boy who was once called incompetent begins!