Twilight Sparkle had always loved dancing. However, she was never very good at it, so she contented herself to watch others. When she heard that Princess Luna was starting Equestria's first ever annual "Lunaris Absolvo" Dance competition she immediately wanted to enter, but remembering all of her past attempts at dancing, with her birthday party being the most recent, she realized she would be laughed out of the competition before the first song even ended. But then she found a tutor in a pony she least expected.
Credit for the cover art image goes to Furor http://furor1.deviantart.com/art/Under-the-Stars-293944012