Twilight prepares for the most important night of her life. But it doens't go exactly as she had wanted...

Story was inspired by SolFoe's Study Interruption

Nightmare Night goes a little differently and leads into a spiraling staircase of events. the Night will forever be mixed with the scent of Lavender.
this is basically my old story Lavender Night, but revised and redone completely, only the basic story elements are there

To commemorate the imprisoning of Discord one year ago, the first annual Celebration of Harmony is starting off with a grand party in Canterlot, something Twilight Sparkle has been looking forward to after many sleepless nights plagued by nightmares. After a chance glance at the party, Twilight and Princess Luna rekindle their friendship sparked on Nightmare Night. Meanwhile, Princess Celestia grows worried over the state of her kingdom, her sister disappearing at odd times, and the seal placed on Discord. Are the princess's worries well founded or is her sister's oddly secretive behavior taking a toll on her nerves? Twilight gets caught between the sun and moon as both royal ponies reveal that there is much that history has forgotten about the nature of the alicorns and even the draconequus.

AU for not taking into account Season 3 canon.

Amazing cover art by Sai, check the image source for more of his great work!

A short story:
Leaving home means leaving all your memories, your tangible possessions, and all the love and hate behind. Time has come for Twilight to do just this. She is scared of the world and all that lays ahead, but she has one special somepony to comfort her as she leaves the world she knew behind.

Follow Twilight Sparkle as she discovers the truth about the royal family and its history when the rise of a third alicorn mare from the past sheds some light on a conflict that took place one thousand years ago. When the world of Equestria ends up being less than ideal or peaceful where will the loyalties of her friends lie? Will she be able to oppose princess Celestia who she has come to love and respect? When friends turn into foes she may just find allies in the oddest of places as the revival of the lunar republic begins. Hidden agendas and mistrust will have to be ignored in order to keep the alliance together.

Will princess Luna be able to stop the atrocities her sister plans?

When the truth is finally heard will the citizens of Equestria act or cling to the desperate belief that they in the end live in a world that is fair and just?

Friendships will break and new ones will be made but what will become of the world?

Princess Luna arrives in Ponyville and begins to do wonderful things in the life of Twilight Sparkle. They become close friends...maybe even more, but when Twilight discovers that Luna may be after the throne the unicorn must choose whether to follow her head...or her heart.

Everypony believes that Nightmare Moon was some dark demon or a servant of Discord possessing Luna, but the lunar princess can't bear to tell them the truth. What really happened a thousand years ago, and how does it continue to influence Luna's mind? Will the power of friendship be strong enough to help, or will Luna give in to hatred once again?
Come one, come all, and join a great new experiment in the writing of collaboration fanfiction! New or experienced, old or young, all are invited to participate!

What would happen if some events happened sooner while others never happened? and others yet that should never have happened happened anyways? Grimdark
TwiLuna

Twilight becomes alicorn of the stars. This is sort of a problem, because Luna kind of already was alicorn of the stars. Oops!

TV Tropes

Luna's isolation and difficult reentry into Equestrian life has left her without the confidence to communicate with the ponies around her. Especially the one pony she most wants to talk to. Celestia is angry, Twilight is upset and it's all her fault. Then she has an idea... She'll invite Twilight into her dreams. What could possibly go wrong?