Seven kingdoms exist in the mysterious planet's hollow, each illuminated by the warmth of the Kingdom of the Sun's core sun. The survival of all the realms is heavily reliant on the radiance of the central star. However, the Sun's Blessing has been weakening, and without intervention, life on the planet is at risk of extinction. Luckily, Fine and Rein, the twin princesses of the Sun Kingdom, possess the powerful magic of the Prominence and are determined to restore the core star's strength.