Luna's has enough to deal with as Princess Twilight's student. Between nightly nightmares of moon princesses and the threat of an old enemy returning from Equestria's past, Luna isn't going to be getting any sleep any time soon
The Elements of Harmony were created many, many years ago. By who? No one living knows. For what reason? No one living knows. To what purpose do they serve? No one living knows. But, one written piece knows and tells all to the willing ear.
Chrysalis has wormed her way into the heart of a mighty empire, and uses the unknowing ponies as pawns in her quest for revenge against Twilight, Cadance and Equestria