The adventure is over! …or is it? After defeating Bowser, Mario and friends discover a Special World! First up, a sparkling sea with a coral color and a trove of treasure! Toadette jumps at the chance to dive in and collect pink coins to unlock the promised prize. What a lovely bonus!

Who is the one in control of this world? Who is behind the scenes, pushing all the buttons? At times they seem to wish to help Toad, while at others they only slow them down, or mess with them for the fun of it. Is this some sort of punishment for all of Toad’s misdeeds? They must figure out the method behind the madness, or else roll with whatever fate has planned for them.

Luigi, the klutz he is, finds himself in an urban landscape swallowed by an endless sea of sand. Worn buildings pierce the horizon as the sun scorches the Earth. Ordinarily, navigating through this place would be impossible, but luckily there are bony contraptions littered throughout to assist Luigi on his adventure. Now he can ride across the sandscape with the help of these Rusty Dusty Rails!

If climbing to space is too hard, how about being launched there? Someone has built a series of devices which are being tested for their ability to send someone flying to the stars, but the proper safety regulations for such devices have been ignored completely! Mario is going to have to investigate the work site fully to make an accurate report to the union.

Larry had the perfect revenge planned for Toad: a huge castle in the sky full of Chain Chomps and dastardly traps. But today's a bad day for Larry, because the Angry Sun has decided to roast every living thing in the tower—including Toadette, who is paying the castle a visit instead of Toad! Larry is desperate to carry out his revenge anyways, but the Angry Sun has its own ideas, activating switches to ruin Larry's traps and set some of its own for Toadette!

After hours of tossing and turning, Toad finally falls asleep. They dream of machines, levers that rise and fall. At first they have control, but soon the machines go haywire, creating a mechanical cacophony that makes their head feel like it’s going to explode. But if they can make it through, if they can find the strength to persevere, there may be something beautiful awaiting them on the other side.

Luigi once more finds himself in a dark, haunted house—an abstruse labyrinth fraught with demented Mechakoopas, erratic Snake Blocks, and a convoluted network of pipes. As he cautiously makes his way through this mysterious mansion, Luigi can't help but wonder why this place feels so familiar...

In a rage over his previous defeat, Ludwig unleashes all of his magic, trapping Mario in a gravity-free dimension where Ludwig holds all the power. Here, taking down Mario should be like shooting fish in a barrel. But if Mario can learn to swim like a frog and find peace in the chaos, he can overcome this trial and trap Ludwig in a cage of his own making.

Bowser has grown tired of playing games. He has unleashed a fleet of tanks upon Discordia, and they are crushing the citizenry under their treads as they roll on towards the capital from four directions. It will take decisive action from Mario, Luigi, Toad, and Toadette to enter each of the main tanks and destroy them from the inside before they end life in Discordia as we know it.