Fairy Castle is a magical world ruled by the Fairy Queen, where Fairies can learn how to use magic and use it to help others. But black magic is forbidden. One day, the Dark Fairy Luna (小月) stole all the black magic and took away the magical Fairy Stone. She wants to learn the secret of the greatest magic and hide into the human world. The fairy, Shirley, who guards the Stone, traveled to the human world in order to find the Fairy Stone and redeem herself, as she was punished for her irresponsibility and trapped inside a music box. She landed somewhere in China, where she was found by two girls: Maggie and Michelle Lin. Shirley became the caretaker and best friend of the two sisters, and with help from the Queen, they transform into fairies and start their quest to find the Stone.
On their quest, they come across Lily, the mysterious apprentice of Luna.