Past And present: A Change

All is good, all is well. The monsters have reunited with the sun and the life of the surface, and with the help of Frisk, they had managed to bud a quaint town.
Except.. Well.. Frisk is having troubles, Chara has found a way to corrupt their mind, and now desires for a genocide run to re-play their nostalgia. Frisk is conflicted, and after a terrible incident, they decided it would be best to disappear and leave all of the monsters in their town, were they would be safe from them. It hurts, but Frisk has already decided.

Now, Sans, he cares deeply for the fallen human, and does everything in his ability to convince them to return. But...will he even succeed? Or will he end up hating them like before?