While having a walk in the Mushroom Kingdom, Mario, Toad and Peach, and Luigi happen on one of the many green pipes, yet a special one. A fairy, which they'll learn is Princess Sprixie, comes out. Bowser is chasing after her, though: he kidnaps her and vanishes through the pipe. Mario and the friends of his can't but promptly jump into the pipe, and they find themselves in the Sprinxie Kingdom, tasked with rescuing the princess.