The Plains is a black and white world with symmetrical patterns etched into the ground. Some small areas can be accessed via numerous teepees, one of which leads to a strange waterway containing Nanashi. The area also contains what appears to be a slain monster that has fallen to the ground.
This area is also home to a wandering, nameless NPC who appears to be wearing a mask. The mask resembles the face of a shy and trembling creature found in the Snow World. They don't react to any effects save for the Horns, and can be killed normally.