Following their adventures in the sewers, Mario and Luigi (along with DK and Cranky Kong) have formed an alliance, and find their way into a secret passage into the Mushroom World via a sewer pipe. It's here that they find out about Bowser's attack on Brooklyn to look for a Super Star that was hidden by the Mushroom Kingdom's princess. Agreeing to help the eager and frightened villagers to rescue her and the star from Bowser's wrath, the brothers and Kongs set off on a grand adventure to stop Bowser's forces as they make their way back to the Dark Lands.
