This story is a sequel to Kamen Rider Unicorn
Sunset Shimmer has become burnt out after constant battles with Dopants and managing any magical mishaps that spring up. So after much deliberation, Sunset has decided to return to her home for a week long vacation.
However, evil doesn't take a vacation, and it springs up in Equestria. The organization known as Shocker, has set its sights on Equestria and threatens all that is good in the magical land. Fortunately, help appears in the form of the "Destroyer of Worlds", Kamen Rider Decade.
But what is Shocker's objective? Why have they targeted Equestria? Sunset Shimmer shall be tested like never before, against foes she has never encountered, see how her metal will be tested in Kamen Rider Unicorn's first movie debut!
Takes place during Kamen Rider Unicorn chapter Initiation