The narrative centers on four divine Dragon Kings, each ruling their own kingdom: one in the north, one in the east, one in the south, and one in the west. These brothers are reborn in the modern world, retaining supernatural powers and the ability to transform into the Dragons from whom they descend. They are content to lead ordinary lives until evil creatures launch an attack against them. The four brothers take on the mission of defeating the "Four Sisters"—four girls from America who are descendants of the "Bulls"—before the latter can use their control over technology and the economy to conquer the world. However, as this conflict begins, the brothers must also find their place in the world while fleeing from the destructive will of the "Bulls".