After another humiliating defeat at the hands of the Mario Brothers, Bowser decides to start recruiting new members of the Koopa Troop to use for his next scheme to take over the Mushroom Kingdom. Among these new recruits is a pair of mysterious, magical jester twins (one guy, one girl) who look suspiciously similar to Dimentio. As they got themselves acquainted with Bowser, they informed him of a powerful object called the "Chaos Star", which, according to the twins, possesses the power that the Koopa King needs in order to defeat his enemies, make Princess Peach/Toadstool his bride, and conquer the Mushroom Kingdom (as well as the rest of the world). However, even though the twins claim to be nothing but loyal servants to Bowser, there just may be more to them, as well as the Chaos Star itself, than they're letting on. Who are these two mysterious characters, and what are their true intentions? When their plan is set in motion, will Mario and Luigi have what it takes to stop them?