Following their encounters with the monsters in the sewers, Mario and Luigi are transported to the Mushroom Kingdom via a warp pipe. There, they meet Princess Peach and King Toadstool, who ask them to aid them in their war with King Bowser, who has kicked them out of their own castle and has sealed it off via the power stars. Now they have to enlist the help of not just the people of the Mushroom Kingdom, but also the people of the neighboring Kong Island and Sarassaland in order to take back the castle and defeat Bowser.
