In a large garage, Mario, Princess Peach, and Toad each create their own karts, and they drive alongside the Kongs back to the Mushroom Kingdom through a secret passage that leads to Rainbow Road. On the way back, Princess Peach begins questioning Mario about the world he originates from and decides to visit Brooklyn sometime.

Bowser decides to have his army use karts of their own to ambush the heroes as they traverse Rainbow Road, with the Koopa General himself chasing Mario with a bulldozer. During the chase, Mario's kart is destroyed, but he manages to hijack another while Princess Peach saves Toad from falling off the road. After losing his second kart, Mario then moves to Donkey Kong's kart, and Donkey Kong fires one of his kart's Rocket Barrels to explode on the bulldozer. Infuriated, the Koopa General locks himself in his winged, spiky Blue Shell and crashes into Mario and Donkey Kong, destroying the latter's kart and a part of the road. The two plummet to the ocean below, much to Princess Peach, Toad, and Cranky Kong's despair, and all of the Kongs besides Donkey Kong are captured and sent to Bowser's dungeon. After landing in the ocean, Mario saves Donkey Kong from drowning, but both are then devoured whole by a large Maw-Ray.