Usual Dusttale events, but the human starts to fear the power Sans is gaining and decides to flee the underground. Unlike Dusttale, the human is ahead of Sans because they are not wasting time killing monsters they encounter on the way. The human warns Undyne of Sans when they encounter her, so the royal guard (including Undyne) head to Snowdin; there, they find Sans where Papyrus used to be, the royal guard confronts him; the battle is pretty equal, so it prolongs for some time. The human continues to head towards New Home, fleeing from every encounter they get; then they reach Asgore and battle Flowey. The save manipulation Flowey does gets noticed by Sans (who was still fighting the royal guard) due to the glitch that caused Dusttale still having some effect, so he flees from the battle looking for the source; when he finally reaches the barrier, he sees Flowey but doesn't see the human due to all the attacks; he proceeds attacks Flowey just in the final moment when the souls are refusing to help him, flowey perishes, and he gains a lot of exp. After the smoke clears up he sees the human standing next to the barrier, he tries to attack but it's already too late, the human has already crossed the barrier and he is left trapped in this cursed reality. After that he goes hiding because he is being looked for by the royal guard, his sanity also starts to dwindle.

Some time after that, Undyne decides to occupy the throne, but Sans comes out and opposes it, of course, Undyne and the royal guard confront him, but this time, due to the exp he got from flowey, he manages to overpower them and crowns himself as the new king and Undyne and the rest of the royal guard start to follow his orders. With his new authority, he orders experiments with determination in order to find a way to reset. These experiments create many amalgamates, too many to keep in the labs; Sans orders for them to be neutralized. They try throwing them in the magma of Hotland, but they jump back up in pain, then they try throwing them in the river, they seem to mostly dissolve in the water of get carried down the current; so they proceed to do that, starting with the ones that were originally in the true lab, endogeny, reaper bird, lemon bread, mERROR (Adress Boundry Violation) program terminated by signal SIGSEGV, core dumped

details: In <ERROR unkown object> 'string: <ERROR could not access type>.name'. Address 0x0000029A is held by process 1478: '???????? ???????? ??□?◆? ??□?■???'

but after some time, the citizens that had drank the water from that river started to report about vivid hallucinations and false memories.

The scientists had to find another way of disposing of this. They thought of a seemingly bottomless pit located in Waterfall, "That will serve" they said...