There are two anime adaptions of the series.
Seven royal families reign over each of the seven kingdoms, prospering inside the planet for many years. Ohisama no Megumi (the sun's blessing) is beginning to die, and it has been forecasted 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 Princess Grace to investigate the reason for the star's decline. Using the power of the Prominence, they hope to rescue the Ohisama no Megumi. An evil chancellor from the moon kingdom named Roman steals the Prominence for his own purposes. After he unleashes the ultimate enemy, evil begins to spread.
The evil power possesses Prince Bright by Boomo. Under evil power, he attempts to rule the entire Fushigi-boshi. Fine and Rein, along with others, try to investigate and defeat the powers of evil that possessed Bright.
Futago Hime Gyu!Edit
Fine and Rein, along with other princesses and princes, leave Fushigi-boshi to attend the Royal Wonder Academy of Education. This prestigious institution is the school where Princes and Princesses from all of the planets come to receive their certification to become Kings and Queens. Upon arrival at the school, Fine and Rein's unprincess-like actions cause them to violate school regulations and lose points. During the orientation of first year students, the vice-principal presents a legendary bell that will only ring when a certain person touches it. If the bell rings, the person is classified to be the "Universal Princess". No princess had ever rung the bell before. But Fine and Rein rang it, and they transformed.
Strange situations have also been occurring in school. A dark entity comes out and forces everyone to become depressed. When someone resists, the dark entity sends monsters that cause extensive damage. One of the first people to become possessed under this entity was Toma, the new president of the student advisory.