This story is set in a geographically diverse land, which includes mountains, forests, and bodies of water. Each region has distinct characteristics held by its inhabitants; Mushroom Kingdom is inhabited by Toads, Moleville is inhabited by moles, Monstro Town is populated by reformed monsters, Yo'ster Isle is where Yoshi and his eponymous species reside, and Nimbus Land is an area inhabited by cloud people. Bowser's Castle is another prominent location in the game, as it holds the portal to the main antagonist's home world.
As in most Mario series games, the main protagonist is Mario, whose initial goal is to rescue Princess Peach (alias Toadstool) from Bowser. However, the story takes on an unusual and very important twist. Soon after the start of his journey, the Smithy Gang invades the world. While attempting to stop the group, Mario is joined by Mallow, a cloud boy who thinks he is a tadpole; Geno, a doll possessed by a celestial spirit from the Star Road; Bowser, whose armies have deserted him out of fear of the Smithy Gang; and Princess Toadstool, who was lost in the turmoil that occurred when the Smithy Gang arrived. The Smithy Gang is led by Smithy, a robotic blacksmith from an alternate dimension with aspirations of world domination
