A mysterious overpowered entity known as Tabuu, master of the Subspace Realm, initiates a full-scale invasion of the Nintendo Multiverse. Heroes and villains from across all franchises are plucked from their worlds again and forced to fight... or unite. The Smashers must battle the Subspace Emissary and save their worlds from eternal darkness, but they can't fight alone, not without more outside forces from galaxies distant from Nintendo.
