Deep in the Ever free Forest, a cave can be found. In that cave, a bright barrier prevents any progress forward. Beyond that barrier is an entire civilization of monsters. When the human Frisk helps shatter the barrier, the monsters emerge and eventually become friends with the ponies of Equestria. Soon after, weird glitches begin, eventually escalating to the point of causing ponies and monsters alike to vanish. A group of ponies and monsters, led by Twilight Sparkle, King Asgore, and Frisk, attempt to locate the source of the glitches and restore the world.