Undertale Dual Pacifists
Frisk had gone through the Underground without killing anyone, and had became friends with everyone, then defeated Asriel by saving him, Asriel then destroyed the barrier with the power of the 6 human souls and all the monster souls and everyone went up to the surface and started living happy lives...but that was not what Chara wanted, Chara then reset to the beginning of Frisk's journey, but something went wrong, now not only Frisk fell down the hole into the Underground, but so did another human, a boy named Alex, and he has memories of before the reset, but those are his only memories, he only knows how happy everyone was, and his name, and is DETERMINED to get everyone their happy ending…