The Elements of Harmony are defeated and Nightmare Moon stands on Equestria's throne as their new Queen. Is Equestria doomed to suffer through night time eternal or will they be... perfectly fine? Twilight finds her new job as slave or "personal assistant" to her new ruler to be a bit maddening. But is this evil sarcastic queen really as bad as she originally believed? And just how many others are diabolical enough to cash in on the change in staff? Can Nightmare truly run a peaceful Equestria? Let me just answer all these questions right here in the description...

Deemed a traitor by the God Empress Celestia, Twilight Sparkle must now flee for her life to escape her inevitable execution. In hot pursuit by Celestia's minions, Twilight discovers a cave where an ancient creature has been kept prisoner for over a millennium.

Luna thought that she had banished the evil within her once the elements had defeated her. She will come to realize that she was deadly wrong as the evil within her comes back with more power than she could have ever imagined.

Nightmare Moon has won, and the world has been shrouded in eternal night. But hope still lives. The land of Equestria is currently divided between the armies of the usurper and those of the Dawn Militia. However, the greatest danger to the rebellion may not be the dreaded Mare of the Moon, but her lieutenant, Eclipse–formerly known as Twilight Sparkle.

Twilight Sparkle has been betrayed by Celestia, all her friends brutally killed in front of her eyes after the young unicorn woke up one morning with wings. Celestia had realized that Twilight had been chosen by the Elements of Harmony to replace Luna and herself as the leading force of Equestria, and correctly surmised that the other Elements would have followed shortly after and become a united force the current princesses couldn’t hope to defeat if they chose to contest their position for the throne. Even though Twilight doesn't want to acknowledge her destiny as Equestria's next chosen ruler, the new alicorn cannot let the tyrants she has now seen Celestia and Luna really are remain in power.
Armed with only the Elements of Harmony and her burning rage, Twilight sets out to avenge her friends and free Equestria from Celestia and Luna's tyranny.
The fate of Equestria, as well as the balance of this entire universe, hinges on Twilight's success.

After visiting the past in It's About Time, Twilight spends some quality time with Princess Celestia before returning to Ponyville. She then falls into a coma and wakes up where no living pony would ever wish to be, and things only get more complicated when Celestia gets an unexpected visit from herself. Featuring Twilight, Celestia, Luna, The Underworld, and some other alicorn etc.

The Princesses find an alien creature barely clinging to life at the scene of a terrifying crash. Can the Combined Power of the Elements of Harmony save it, or more importantly, should they save it? Will the arrival of this strange creature tear Equestria apart?

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https://tvtropes.org/pmwiki/pmwiki.php/FanFic/Article2