A young teenager named Mikari Otohime is struck by lightning and sent to Equestria. Upon realizing she's been turned into a pink-and-black Alicorn, she's more annoyed than freaked out, because pink is still a Main Character trait.
Besides, this isn't the first time a Narrative's pulled her into a new body or world, and if she can get back home, it most likely won't be the last.