With the events of Super Mario Bros. 2 behind them, Mario and friends have written off the land of Subcon as nothing but a peculiar dream. Their quiet lives are disrupted once more when Wart returns, this time seizing control by overthrowing Subcon's rightful king. Mario and his allies must face the Birdo trio, Mouser, Tryclyde, Fryguy, and Clawgrip all over again.