The Plain is the fourth stage of the Subspace Emissary. Mario & Pit appear here right on the Ancient Minister's Path. The duo go through the Plain with enimies ahead of them.Media:youtube.com/watch?v=gli_WOY95yY.ogg The enimies are:
Primids, Borboras, Feyesh, Tickens, Boom Primids, Spaaks, Fire Primids, Glunders
There is a secret room which contains 2 stickers, a Heart Container, and a yellow box. After you pass the level, a cut scene appears showing Mario & Pit trying to grab the Ancient Minister but fail.