Takes place during Mario and Luigi: Superstar Saga, just after the Koopaling boss battles.
After the Koopalings fail to defeat the Mario Brothers, the evil witch Cackletta banishes them from Mushroom World. The children of Bowser soon find themselves in a strange world populated by strangely-colored talking ponies with a strange fascination with the concept of friendship. While Princess Celestia works on a way to send them back, Ludwig, Lemmy, Roy, Iggy, Morton, Wendy, and Larry must each move in with various ponies in town and adjust to life in a world where kidnapping princesses is not a normal occurrence. Will the Koopalings finally break free of the monotony of being Daddy's Little Villains and make some real friends? Will they finally have the chance to carve their own paths in this world, and pursue their dreams? And most importantly, what will happen when they finally can go back? Will they want to?
Rated T for some minor language and some crude humor.