Luna jumped in front of Twilight. "This has gone on too long, sister. You cannot keep wiping ponies minds when they find out something they shouldn't have. You have had free reign for long enough. It ends now!"

Celestia laughed. "Silly, silly Lulu. Wiping minds only works for a few years at best. When they remember again, I kill them. Just as I will kill you. Take comfort in the fact that Twilight will be happy during her final few years of life, living in my castle as a servant. Mindlessly obeying my every word."

Luna screamed as flames engulfed her. Twilight felt magic flood her body as everything went black.

Twilight woke up in a dark library, shivering and in pain. Scattered around her were the Lunar Diaries, her notes and a sealed scroll. She opened the scroll.

Twilight gathered up the Diaries. "Well, let's get started."

Twilight stood in front of a bare portion of the library wall. "The Luna vault should be here. Where did I put the pass code? Aha! Movus nottus Tiaus largus buttus duetus eatus muchus cakus andus desertus!" The wall slowly disappeared. Inside the vault, there was countless scrolls, weaponry and gem-bound spells. At the back, a large banner hung on the wall. The crest was Two rapiers crossed under a full moon. "Wow! She has enough weaponry to outfit several armies worth of Battle Mages! Why didn't see just team up with any of Equestria's enemies, instead of depending on me? She must trust me a whole lot." Twilight made her way to the section marked 'Moon spell' and started her research.

"Yes! I assembled the spell properly! It only took me forty-two tries." Twilight held the orb up to a torch. The light was sucked into the orb, leaving cold black flames frozen on the wood. "Celestia won't stand a chance against this. I hope I won't have to use it."

Twilight stared at the blank page before her. "I can't believe what Celestia did. I looked up to her, I considered her my second mother." A few tears fell to the paper. Twilight took a deep breath and started writing.

Twilight Journal; Entry 1

I am writing this journal to keep track of my thoughts and the current events. It is my hope that if I should fait, somepony else will be abled to continue my work. Celestia, the current Alicorn of the Day has either gone insane or is evil; possibly both. In order to protect 'her ponies', she is brainwashing and killing anyone who doesn't believe she is the epitome of goodness. She even attacked her own sister, setting her on fire.

Twilight choked back a sob as she stared at the paper. "Oh Luna. Why didn't you just run? I'm just a unicorn, not much I can do against an Alicorn," Twilight whispered. She got up and stretched her stiff muscles. It was much colder in the Lunar Palace than she was use to in her own house. Luna has used her magic to send Twilight to the one place Celestia could not follow; the moon. She picked up a few papers that had fallen off the obsidian desk and sat back down.

Events leading up to possible regicide:

July 16th; received The Lunar Diaries from Luna.
July 20th; decoded first entry.
July 21st; sent report to Celestia, summoned by Luna. Luna assaulted by Celestia. Twilight Sparkle sent to moon.
July 23rd; decoded entries specified by Luna.
July 28th; completed Moon spell.
July 29th; started The Twilight Journals.

What I found the decoded diary entries was horrifying. Celestia is not the benevolent ruler we thought she was. In actuality, she's a power-crazed dictator. Here are the Diary entries Luna instructed me to decode.

Entry 84756
My sister has done the strangest thing today. About 50 years ago, my sister outlawed talking about me. Now, she changed the school curriculum to teach a different version of our war. An evil entity known as Nightmare Moon descended from the moon to plunge the world into eternal darkness. She masqueraded herself as Celestia's long lost sister, then attacked once She was trusted. I do not know what she is trying to do, perhaps assure that when I return I won't be held accountable for my actions? I will wait and see how this plays out.

Entry 210043
I cannot believe it! She has successfully erased all mention of me from history. The only place I exist is in her personal notes and books. I truly hope I am wrong about what she's doing. If I am not, then I will have the fight of my life when I return. I am very glad I have perfected all my battle spells.

Entry 645244
I entered my Sister's dreams tonight. She dreamed about how she convinced our subjects to ignore me. She was the reason I was ignored. She caused my pain and sorrow. She wanted me to rebel! She wanted all the power to herself! I will never forgive her. She thought I was powerful before? I was holding back. Unlike her, I did not want to kill her her, only get some attention for once. Now, she will face the full power of the moon. She will beg me to end her suffering. Celestia will spend eternity as one with the universe. I will forcibly dissipate her essence across time and space.

Entry 730250
In a few hours I will be freed. I will return to Equuis as Nightmare Moon and use the Mind spell. It will buy me a few years to befriend these new Bearers. I will stop you, sister. I will free my subjects from your tyranny! I have known for a millennia that the Moon spell requires Magic itself to cast it. Now, you have handed her to me. Your destruction will be at your student's hand. Oh, the irony! You are the self-proclaimed defender of Harmony, and a Bearer of Harmony will kill you. Sweet dreams sister, for the Nightmare is coming.

Entry 74
Of course! Now I perfect my Mind spell. Too late for it to matter. I'm trapped on my own moon. I was stronger than her, so she used the Elements. We swore to never them on each other! Even if one of us turned evil. I'm not evil, am I? All I wanted was for ponies to look up and say "What a beautiful sky tonight! Luna works so hard, thank you, Luna." All I wanted was to be respected. To be loved. Is that so much to ask for? To be loved! But no, you took all the credit. You brushed my concerns about being feared and ignored off. Look where it got us! Separated for a thousand years. Why...

The Mind spell: will implant absolute trust for you in the target’s mind. Will wear off at a rate equal to their magical prowess.
The Moon spell: will convert a being whose power source is some sort of light, into distilled moonlight. If target is not on moon or near a moonstone, essence will dissipate forever. Instructions for casting in vault £|_||\|@

Over the course of Luna's banishment, Celestia removed all traces of her existence. She also prepared to kill Luna the second she was released. I see no other option than to use the Moon spell on Celestia. She has murdered an untold number of innocent creatures. As the leader of the Bearers of the Elements of Harmony, it is my duty to bring Celestia to justice. I will assemble a force strong enough to take Canterlot. Before attacking, will of course give her the chance to surrender. There are spells that can bind even the magic of an Alicorn. If she refuses, I will have no choice but to use the Moon spell and trap her essence in a moonstone. I really hope I succeed. If I don't, I'm dead, or worse; a mindless servant.

End of entry

Twilight sealed the journal with magic, and picked up two short swords. "I'm coming for you, Celestia. It's time I taught you the error of your ways." Twilight charged up her magic and released the teleportation spell, picturing the Badlands. She opened her eyes to the library. "Why didn't I end up in the badlands? This is an easy spell, on Equuis." Twilight threw her swords at the wall. Only Alicorns could move between planetary objects. She sat down and looked at the ground. A book was laying open to a chapter named: How to Become an Alicorn. She picked up the book and started reading.

The spell to change unicorns into true Alicorns was remarkably easy. Inscribe runes inside a magical circle, say the the spell and voila! A new Alicorn. "Why haven't more ponies done this? It's so simple. Although it has an expiration, you can cast it as many times as you want." Twilight stepped into the circle and recited the ancient words. A flash of light blinded her momentarily. When she could see again, she had two beautiful purple wings. She dropped the book and teleported to Equuis.

A small piece of paper fell out of the book.