In the magical underwater world, there is a mysterious and charming place called Hai Ying Bao, a.k.a. the Ocean Castle. When human girls Ling Haixin and Xia Fan accidentally met the Princess of the Icy Blue City, Na Xiya, they transform from ordinary girls into magic fairies. Together with Xiya, they protect the human world and the sea world, helping her investigate who is polluting the ocean. (Source: Balala the Fairies Wiki, edited)

After the fairies defeated Gunala, the Evil Goddess, another crisis hit the Fairy Castle!! The magical energy of the world has been devoured by the evil wizards. The Rainbow Flower, the source of the magic power, is soon to wither, and this will destroy the world of Fairy Castle. Only finding the legendary Rainbow Heart Stone and letting it recollect all the essential energy can save the world. To solve this biggest crisis in the history of the Fairy Castle, Prince Youle, Xiaolan, and their new friend Xiaoqian, have to go back to the human world and reunite with Meiqi and Meixue to fight the evil again. 
 
(Source: Mahou Shoujo Wikia, edited)

Not far from the Magical World of Fairy Castle, there is another Magical Kingdom called Colorful Castle. Which is a place full of color, joy and humor, just like a peaceful, carefree paradise... Until one day, at the edge of the Kingdom, There a dark gray island, where the owner of it, The Lord of black curse just woke up from sleep. In order to make his island to become more powerful, he decide to steal the "Color Magic Energy" of Colorful Castle for himself. The Lord sent his men, the Black Bean Soldiers, sneak into the colorful Kingdom, to steal the energy. Witnessing her own people been bullied, the princess of the Colorful Kingdom found herself had no strategy left to try, as herself had been cursed by the mysterious curse, and turn into a little pixie. But she would never thought, there will be three girl from the human world, to be on her side, together, they will dealing with the Lord of the black curse. Also, the peaceful and joyful atmosphere of the kingdom, is going to be changed along with the girls break in.
 
(Source: Mahou Shoujo Wikia)

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