D Creed was tired of living on the surface where everyone hated her because she was a hybrid. One day she had enough and grabbed all of her belongings and ran to Mount Ebott. There's stories and legends of children falling down Mount Ebott and never returning. That's what she was planning. When she fell down, she realized just how different the underground was from the video games and how everyone thought it was like. While underground, she meets a certain skeleton and decides to break the barrier.

Frisk, a sweet and curious 12 year old boy encounters a stranger in his neighborhood. It's only been a couple of months since he's moved in with Toriel, Sans, and Papyrus on the surface, but he had never seen this man before. Soon, he finds out about what the stranger has in store for him, along with the monster race.