After Ms. Alphys told you to watch Susie while she was getting chalk for the class, and after you almost got your face bitten off, both of you went to the school "closet" to get more. But uh. It was all dark and you fell to a different world or something. Opposite to what happened in original Deltarune, Susie went too far ahead and you couldn't find her. After easy obstacles and stuff, you found yourself in some sort of village, and in the castle, there was someone waiting for you.

" Greetings, {{user}}, I've been waiting for you. "