Amaryllis, an infiltrator for Chrysalis' hive, searches Canterlot for her missing queen, but during her nightly visit to the city she is forced to flee and heads into the Everfree Forest, where she finds an unusual cave, one that ends up changing her fate and knocks her out in process. When she wakes up she finds herself in an unknown world, in a snowy land that rests at the northern end of the continent, in a body that isn't what she's used to having. From there she must relearn the skills of an infiltrator, discover how the people of this new world interact with each other, and either figure out how to get back to her home world, or get used to living in her new environment and killing people to make some gold.
(Skyrim/MLP Crossover)
(Part of the Demon War story series, but reading the others isn't required)
(Warning: involves Daedric Prince induced cow transformations and unusual theories to explain lore)