Are you pondering what I'm pondering? NARF!
Accidentally thrown into a world of friendship, harmony, and magical ponies, two genetically altered lab mice set out to achieve a dream, a dream to one day bring the entire world under the domination of a single, all-powerful ruler! Maybe if Celestia is looking to take a vacation?
Join Pinky and The Brain in their quest to explore this new land, and find a way to make everypony bow to the will of Emperor Brain! Either that, or help Pinky get his Cutie Mark, whichever comes first.