We all know the story of Undertale, about a human who falls into the underground, befriends everyone or kills everyone, but what if during the war between humans and monsters, the monsters won? This is the world of UnderBound, a tale about a monster who falls into the underground, and meets various humans. Except, these humans are various Earthbound/Mother characters. Join the fallen monster as he goes through the underground, encounters strange humans, and make friends.