My Little Pony Friendship is Magic Twilights Kingdom Preview

here's a description for part one of "Twilight's Kingdom":
When a villain escapes Tartarus, Princess Celestia chooses Discord to help track him down instead of Princess Twilight. Meanwhile, prompted to prove that she has an important role to play, Twilight turns her focus to opening the Tree of Harmony chest.
And part two:
In order to protect their magic, as well as the fate of Equestria, Princess Celestia, Princess Luna and Princess Cadance transfer all of their magical power to Twilight.