In the hollow Mysterious Planet, seven kingdoms co-exist, all of them lit by the Sun's Blessing from the Kingdom of the Sun, in the middle of the planet. The light of the core sun is necessary for the continued existence of all the kingdoms. Yet, something is causing the Sun's Blessing to weaken. If something isn't done, it will be the end of life in the Mysterious Planet. Fortunately, the twin princesses of the Sun Kingdom, Fine and Rein, have been endowed with the magic of the Prominence, and are looking for a way to fix things.
Seven royal families reign over each of the seven kingdoms, prospering inside the planet for a long time. However, Ohisama no Megumi or the internal star is beginning to die, and it has been forecast that it will disappear in one year. If it disappears, all of the planet will be covered in darkness. Twin princesses Fine and Rein receive a secret mission from Grace to investigate the reason for the star's decline. Using the power of the Prominence, they can hope to rescue the Ohisama no Megumi. Fine and Rein, along with Poomo, a fairy-like follower given to the twins from Princess Grace, power up with princess levels and attacks to get more powerful.[Edit]