When Sunset Shimmer steals Twilight's crown she ventures into a new world with humans who play card games. She then meets Yugi Moto and his friends. In order to win her crown back she must beat the best of best including Sunset Shimmer.
In an alternate unvierse, Cadence,sells her identify to Chrysalis the Changling Queen. A story inspired by Disney's The Little Mermaid, but not a direct retelling of it with ponies.