Someone who doesn't know how to describe herself, is always struggling with debilitating depression, and won't stop hanging onto the hope that happy endings are possible.
Sometimes it can be very, very hard to remember --or believe-- that you're awesome. Fortunately, that's what friends are for. (Sunset Shimmer checks on Rainbow Dash.)
After rumors of magical events, Daring Do comes to Canterlot. Concurrently, Sunset Shimmer finds herself burdened with an overabundance of free time. They talk.
Ok, so, simple drill: went to a place, bought a thing, was transported to another place as a person. Now I'm living in a displaced story; never actually read one, but I assume they suck. Urgh. Question now is, "What would Tsukasa do?"
At her lowest point, Sunset meets Adagio, Aria, and Sonata, human teenagers who have never heard of Equestria and have no idea what the students at CHS think they've done.
When they started dating, Sunset was at her lowest point and Wallflower was just as miserable. Now things are getting better, and they weren't prepared for that.
After Sunset convinces them she's innocent, Fluttershy and Rainbow Dash become the pariahs of CHS alongside her, and Anon-a-Miss keeps posting into the new year.
With everyone convinced that Sunset Shimmer is Anon-a-Miss, Sunset finally gives up. She's saved by strangers, a couple of whom have familiar faces. (Authorized remake of The Fall of Harmony/Like the Phoenix)
After Anon-a-Miss utterly fails to separate Sunset Shimmer from her friends, a video of the magic at the Fall Formal is released online for the entire world to see.
When Sunset Shimmer hopped a freight train to Canterlot, a place she left as a child, she didn't expect people to know her name, much less blame her for something she didn't do. Meeting herself didn't make things any less confusing.
In Canterlot castle there is a quadruple locked room. They say no one ever goes in or out. They say a mare lives inside. They say meeting her is courting death. How does one respond to that?
In the aftermath of (Dainn's version of) the Anon-a-miss incident, Sunset Shimmer forges her way without the five girls who were supposed to look after her.