It's been 500 years since Celestia had to banish Nightmare Moon, with Luna, in the moon. One day, she is given a special stone as a gift that can grant one wish. Celestia wishes to have the Luna she knows and loves with her again and her wish is granted. The sisters are together again and couldn't be happier. Until they find out that Nightmare Moon is still trapped in the moon and will still return someday. Now Celestia and Luna must work together to put the very embodiment of their mistakes to rest once and for all. So Celestia starts making plans for the future. And to protect her reputation, Luna hides her true identity and pretends to be Celestia's cousin in the meantime. The two of them will learn more about each other and grow closer as sisters over the next 500 years.