Twilight grew up and found her destiny, but there is one pony who feels embittered that it should have been her destiny, her glory. Breaking Dawn, Celestia's former student, is convinced that she is the true Element of Magic and has been robbed of her honours, her fame and most importantly of the love of Princess Celestia without which Dawn is nothing.
Rallying her old friends, Breaking Dawn sets out to bring Equestria's newest princess down and pass the final test her mentor set her all those years ago. As Dawn begins to wreak her vengeance, and Twilight struggles to protect her precious ponies from her elusive adversary, both these students of Celestia embark upon a dark path, paying no heed to the truth that a quest for revenge can only end one way.
Princess Twilight Sparkle comes under attack by a foe seeking revenge for something Twilight does not even remember. It seems that finding your destiny can steal others' away.
Sunset Shimmer returns to Equestria determined to save her home, but at such cost that destruction might be preferable. With Twilight imprisoned in the Labyrinth Box and the Mane Six captured the hopes of Equestria rest with the CMC.