The kingdom of Gemini is attacked by the evil Queen Halle. The twin princesses of the kingdom are missing, so is the important Night Star Box, which has affected planets including Earth. The fairy Queen had sent Prince You Le and Sally to Earth, looking for the Night Star Box with the help of Maggie and Michelle. Then the gang found out one of the girls who takes dance lessons with Maggie and Michelle is one of the missing princesses, Bei Bei! The mission to find the Night Star Box and the the still missing princess, Ya Ya, is now on the shoulder of the fairies.
(Source: Mahou Shoujo Wikia, edited)