Sunset Shimmer finds herself in a strange place, with familiar faces but not so familiar lives. Some time ago, she lost contact with princess Twilight and Equestria, at the same time, her friends suddenly did not remember anything of Equestria. Since then, she is searching for answers, hoping that her fears weren't true.
What about the rest of the Equestria Girls cast?
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I'll give details in a future chapter, where Sunset tells her story for her citadel friends.
For now, all I can say is that the loss of memory from her friends of canterlot high is related to what happened with Equestria.
Keeps it up! Put your collective heads together!