Celestia leaves to deal with a foreign crisis, giving her sister a chance to rule alone and become more attached to the modern world. She calls on Twilight Sparkle to advise Luna, hoping her student will be able to draw Luna out of her shell. With two major threats to Equestria already defeated in the past year, it seems like the perfect time to let Luna gain some confidence and experience in the modern world. After all, what are the chances of a third disaster occurring?

Now comes with complimentary tropes.

We all wear a mask called composure, beneath which hides a heart that twists with guilt and hidden feelings. Regal as she is, Princess Celestia is no exception. What might be revealed should circumstances cause this mask to slip - or break?

Set several years after the potential conclusion to the series.

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

As Twilight Sparkle kept studying about the wonders of friendship, she evidently came across love and romance. And soon after she had been studying these new aspects, she suddenly began to feel a wanting that her friends simply couldn't fill in her heart. So Twilight Sparkle decides to use a shape shifting spell to change her appearance to hide her real identity and travel to Canterlot to find somepony in the city's night life that she could try to have an anonymous romantic moment with. But she wasn't the only mare who had planned exactly the same thing at the exact same day, as the lunar princess had decided to do just the same. So they meet each other by change at a party. Unknown to either of them who the other mare really is and that the shape shifting spell they both use will only last until the first morning sun rise.

Everypony is invited to the celestial sisters' grand Christmas Eve party, where Luna's encounter with a mistletoe and a sudden lavender mare causes quite a few risen eyebrows.

Twilight finds herself enthralled by Princess Luna and everything she represents. As Celestia's pride and joy, Twilight struggles to repress these feelings. But an old and well-known evil surfaces again at the worst time. Can Twilight fight off the spectres of the past?

Princess Luna knows a thing or two about nightmares and dream magic. Her duties at Night Court have become tedious. With the help of some forbidden power she reaches out to a certain Element of Magic for the companionship and knowledge of modern Equestria she desires. But while Luna is distracted and Celestia sleeps, an old evil returns with plans both dire and terrible and a new evil plots under their noses.
(Story takes places roughly between season 2 and season 3, so post-changlings, pre-Sombra)

Cover image by JJ at lovetomorrowlove.tumblr

Twilight ventures out into the mountains to see a once-in-a-lifetime event. Disappointed by her friends not coming with her, Twilight crosses paths with a kindred spirit.

This story is a sequel to Off The Edge Of The Map

When Twilight is sent with Luna on a diplomatic mission to Draconia, they quickly find themselves somewhere that doesn't appear on any map, and Luna is lost in more than one way...

Thanks to RBDash47 of Pony Fiction Archive for formatting it for submission.
Title image by Valcron

Tremendous thanks to Illya Leonov and Scribbler for the Audiobook version.
Now with a Spanssh translation by SPANIARD KIWI: https://www.deviantart.com/spaniard-kiwi/art/Apoteosis-2-3-857110089

Twilight Sparkle is whisked away to the utopian city of Canterlot, where she has been invited to participate in the legendary Aura Bloom magic competition. While there, she runs into an old nemesis.