It has been two months since the Monster Kingdom was released to the Human World. The humans are showing slow signs of acceptance but most importantly, Frisk has been accepted into a new family with Toriel and Asgore. (These are my story events and this is my Fanfiction. None of this is canon.)
After stopping Chara's plan to destroy the RESET button, Frisk realizes they are far from safe. Asgore is dead and the castle is being guarded constantly to make sure Chara doesn't return to finish her plan. Then...just as things begin to shape up....they fall apart in the worst way...
After the death of Frisk, Asriel, wracked with greif, reset the game. Oddly...since someone else pushed the button, not everyone lost their memories. And some are recovering older ones that leaves Frisk wondering who can be trusted.