From the Animeraider:

Maiko is the daughter of a famous ballerina and in her 2nd year of middle school. She is studying to follow in her mother’s footsteps, and her grand dream is to dance with her older brother who is also a dancer and has left home. But there’s another dancer in the wings, a girl named Chiyako who was born on the same day and in the same hospital as Maiko…