A long time ago, a goddess created the Land of Valentine and the Land of Lupercalia. Within both land held the keys to destroy the world. Once the keys come together, there will be no stopping the world from ending. Within the world, she made sure there would be four protectors in Valentine and one in Lupercalia. 

Years later, this became nothing but a legend to the people. However, in the Land of Valentine, the people of sky kingdom can not help but worry about this legend and therefore created four girls to prevent the world from being destroyed. It was their attempt to stop world destruction. Each girl was sent to each land; the land of the water, the land of the sky, the land of the earth, and the land of the underworld. Once the underworld discovered their plan, they sent four boys whose mission, and sole purpose of life, is to stop each girl from preventing world destruction.