The heroes of Super Mario Bros. 2 return home and decide that the fantastical world of Subcon must have been nothing more than a vivid dream. That comfortable belief is upended when Wart makes his move, overthrowing the King of Subcon while the Mario crew looks the other way. Facing the same foe in what feels like a continuation of that so-called dream, the group must again defeat Wart's forces — led by the familiar Birdo trio, Mouser, Tryclyde, Fryguy, and Clawgrip.