Neo Domino City is a war zone.  The mysterious Black King has spread his shadowy influence throughout the once-thriving metropolis.  A small resistance movement is fighting against him, but they can't last much longer without help.

In Equestria, the balance is beginning to shift to the darkness.  Twilight Sparkle and her friends are sent across dimensions to the human realm to discover the source of the imbalance and to repair it.  But she'll discover much more than that, and will eventually learn the true connection between her universe and Yusei's.

It has been two years since the events of Yu-Gi-Oh! 5D's.  The Fortune program had been successfully installed into the Momentum Network, ensuring that it would never go out of control again and it seems that all is at last right with the world.

But when Yusei hears the voices of his Equestrian friends crying out through an anomaly in Satellite, Yusei revs up his D-Wheel once more!  An old foe has returned to finish his mission once and for all, and it's up to Yusei to stop him!  Can Yusei find and stop the sinister Paradox before his time-jumping destroys Equestria and his future?

This wasn't supposed to happen, but I said that I could come up with a sequel if I wanted to and my brain mistook that for an order.  This story was born as a result.  So hang on tight, my bronies!  This is gonna be one hay of a ride!

After saving the future from Paradox, Yusei prepares to return to his own time.  But when the Crimson Dragon veers off course in the rift, Yusei finds himself in a strange new world... populated by brightly colored talking equines.  Yusei meets Twilight Sparkle and her friends and becomes their friend as well, even teaching them how to duel.  But something isn't sitting right with Yusei and he soon learns why he was brought here when an ancient enemy reappears and goes on a destructive rampage.

This is my first attempt at pony fanfiction, though not my first try at writing in general.  I have no idea how this is gonna go, but be honest.

Regarding the duels: I intend to describe the actual gameplay just as much as the monsters and card animations.  I'm not just a fan of the Yu-Gi-Oh! franchise, but a Duelist myself.  As far as the rules go, I'll try to help the unfamiliar understand the game in the beginning.  Card and player stats will also be displayed during the duel portions of the story (I'll try and write it so that they don't disrupt the flow of the story too much).  But beyond the stats and character descriptions of their cards, you'll have to look stuff up yourself.  You can do so on the Yu-Gi-Oh! Wiki.