The portal between Equestria and Sunset Shimmer’s world has closed unexpectedly. Despite Twilight and Sunset’s best efforts, the girls have been unable to come up with a solution. Running low on pages to talk across the dimensional rift, Twilight reads what might be Sunset’s final message to her. However much to Twilight’s surprise, there’s also another message to a different pony.

Inspired by a conversation with Tired Old Man and the story The Last Page, with apologies to Holy.

Sunset Shimmer has finally rebuilt her life at Canterlot High. She has friends, she's in a band, people like her, everything's going great...

And then out of nowhere, she turns back into a small talking unicorn.

Now, with the help of her friends, she has to figure out why she's suddenly a pony in a human world, and whether or not she can become human again...or will have to leave her new life and go back to Equestria.

(Cover art vector sources: Elsia-pony, TheShadowStone)

Now with a TVTropes page!

Sunset Shimmer, twice savior of Canterlot High who earned her wings by using the combined magic of the Earth elements of harmony to save the world from Twilight Sparkle (you know... the one with the glasses). She's offered to help Twilight's (you know.. the alicorn Princess of Friendship) new student learn about friendship while the whole crew embarks on a trip to the Crystal Empire. This should be a fairly relaxing and stress free trip. Right? RIGHT?!

It should go without saying, but MAJOR spoilers to the season 6 premier.

Sunset vector by mighty355. Other cover art stuff by Novel Idea!

This story is a sequel to How Not To Use Your Royal Prerogative

  In an Equestria where the Sonic Rainboom never happened, Sunset Shimmer is the prized pupil of the Princess of the Sun. As Sunset struggles to make up for her past misdeeds and come to terms with the pony she wants to be, Celestia sends her to find the classic work The Application of Unified Harmony Magic from the Royal Canterlot Archives.
  Right after lunch, some meddling by her friends and meeting somepony with firsthoof experience of the Sunset she used to be.

Featured on Equestria Daily on August 18, 2016!
Appeared in the FimFiction Featured Box!

Cast: Sunset Shimmer, Moon Dancer, Minuette, Twilight Sparkle & Princess Celestia

Stories set in the Wavelengths Timeline in chronological order:

Origins Arc
The Alchemy of Chemistry
Bards of the Badlands
Grading on a Bell Curve
Habits of the Equestrian Phoenix
How Not To Use Your Royal Prerogative

Applications Arc
The Application of Unified Harmony Magics
Princess Celestia: A Brief History
The Cloudsdale Report

Dreamers Arc
Tactics of Snowbound Unicorns
A Study in Chaos Theory
Teahouses of Saddle Arabia
As the Raven Flies

Cover Credits
Cover Design by Amber Spark
Sunset Shimmer Vector by TigerBeetle
Pony SciTwi Vector by Osipush
Canterlot Bookshelves Vector by FavoriteArtMan
Sunset Shimmer Cutie Mark by MillennialDan

Beta Reader Credits
Ebon Quill - Worldbuilding Writer on The Manehattan Project
Quantum State - Technical Director of The Manehattan Project
The Albinocorn - Master of Sunset Shimmer Stories

Strongly Recommended Stories:
The Brightest and the Best by Pineta - The events in this story are considered to be completely canon to this timeline and explain Twilight's entrance exam to Celestia's School for Gifted Unicorns. I cannot recommend this story enough.
MLP Annual 2013 - "The Fall of Sunset Shimmer" - As above, the 8-page short comic in the beginning of the Annual is also considered to be canon, though with some major variations.

Version 3.0 Edit: Extensive grammatical and mechanics changes. Adjustment to timeline of Sunset's second mirror experience.

Sunset has made a lot of mistakes in her life, but has never dared to confront her deepest fears and guilty deeds. Now, one trip up to a mountain lodge with five of her closest friends is going to change that. And change her in the process.

Written before Friendship Games aired

After her little magic trick at the Fall Formal, Sunset Shimmer is not having the best night, and it's about to get worse: Principal Celestia just found out that Sunset has been living in the school clock tower. Now she has nowhere to live, and who's going to take in a teenager with personal issues that include recent demonic possession? No one normal, obviously.

But... maybe someone with a mohawk, a house full of creepy masks, and blue eyes that seem to see more than words -- or rhymes-- can say.

Winner of the Writeoff Association's February WriteOff, "Look, I Can Explain."

When Twilight received a letter from Luna informing her of Princess Celestia's death, she had no idea what to expect. However, nothing could have prepared her for what followed.

Written for the 13th F*** This Prompt contest.

Special thanks to fourths for editing.

One day, Twilight Sparkle discovers something amazing about her friend Sunset Shimmer.

She's a magical talking pony!

This requires investigation! Science! Possibly a full-body physical!

Or maybe Twilight will just ask her what's up with that.

Rated Teen for frank discussions about... y'know.

Sunset Shimmer loans Pinkie Pie a thumb drive.

Except that it's the wrong thumb drive. And that it contains exactly what you'd expect to find in the wrong thumb drive to loan away.

Rated Teen and Sex for discussions of pornography and self-love.

[Now with a parody version!]
Sunset Shimmer: Ex-Queen bee of CHS. Ex-She-deamon. Ex-villain. Overall bad-ass.

However, as the hair 5 are learning, Sunset isn't all she may seem to be. This confident girl may just have a secret or two that she doesn't want out.

((Edited and altered 5/8/15))