21 parts Complete MatureWritten: May 10th, 2017--June 22nd, 2017
reposted from my AO3, anonemones; contains both part one and part two.
After a year of living on the surface, monsters and humans have gotten along well, with (mostly) everyone adjusting to the many changes without much trouble. However, events take a strange turn when Sans and Papyrus--both of whom have been acting unlike themselves--go missing, supposedly without a trace. In their place are two monsters who go by the names of Wingdings and Aster, twins, claiming to be the lost Royal Scientist. Everyone is thrown for a loop, especially as nobody remembers a Wingdings or Aster--or, as they claim to be, "Dr. Gaster"--nor do they remember a Royal Scientist before Alphys. And with Sans and Papyrus missing, things don't look good for either of the boys.
As their friends search for the missing skeletons, Wingdings and Aster work together to uncover what's happened while they were gone, as well as what might've caused everyone to forget them in the first place. But, trouble lurks within the shadows, as the Void closes in on them once again--refusing to let go of what belongs to it. And unfortunately, the Void is not the only thing after the boys' lives.