Hilarity ensues when the pragmatic & well-mannered Arbiter and his intelligent-defunct friend the Master Chief find themselves on Equestria with absolutely no idea as to how they arrived.
When Discord hears that his own creation, poison joke, continues to flourish in the Everfree, he simply cannot resist a good prank. Poison joke in hand, he storms Canterlot Castle.
Half a year has passed since Twilight became a princess and gave up the elements of harmony. Canterlot is under siege and only Discord and Pinkie armed with the next generation of princess gatling guns may save the day.
It's Princess Twilight vs Discord in the greatest game to never be sold on store shelves because of, but not limited to: loss of sanity, rage quitting, and LOTS of statue abuse.