Starland is a planet that is full of hope and light. However, long-oppressed darkness is awakening and threatens the dimension starting from Starland. Lord Stephen Hugo wants to take revenge and power that lost to his kingdom for a long time ago. His sole aim is to reach the ultimate potential of the cores and to become the emperor. The Harmony Dimension is facing an existential crisis. The princesses of the five kingdoms, Rainbow Guardians, have to stop this course before it's too late.