So, two humans wind up in Equestria as ponies. Problem is, they wind up as the same pony and now have to share a body. If only that were the end of it though...

Twilight Sparkle receives a Duel Monsters deck from her mentor, princess Celestia, and is told to participate in the Summer Sun Celebration tournament. However, there are more to these cards than just color on cardboard and confusing rules...