The darkness that took control of Stygian was banished to another dimension, little does anypony know that's what it wanted. It summons Twilight and her friends to that world to drain her alicorn magic and combine it with the dark side of the force to be contained in a crystal known as the cosmic crystal. They get captured by a group of bipedal creatures and get saved by another group of bipedal creatures, one of them being hairy, and they meet two robots. Will the Ponies and Dragon return to Equis? Or will they stay be stuck in this galaxy while it has a civil war going on.

Note: Takes place one year before 'The Empire Strikes Back'.
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My Little Pony belongs to Hasbro
Spoilers for season 7 finale