Season 5 of Undertale Rewind Begins in The depths of underground, way lower than it was before.

The Team (Undertale cast) Went through the cave, as furgeson (turtle shop keeper) knew a location to an Ancient Hourglass, The Prophecy is talking about a one or two Souls can Retreat the time, back to its own grid, however Frisk had not much power to control the Hourglass, so they had to resort going for one timeline..or so said universe itself.

The Hourglass Spirit has spoken about an Eye that has knowledge on how to get the 2nd soul and combine with Frisks power.

The Spirit Talks about.. Prunsel. Sans remembers the eye he saw the eye in the dream, talking about not revealing the Hourglass as major consequences would have happen

Sans dosent know where Prunsel is, so they decided to travel to Another Timeline to caught Prunsels attention.

DUSTTALE.

In that universe, The Team Falls down to Snowdin,Thinking they're back to where they are from before but unbeknownst to them, they see dust, everyone being gone, grillbys demolished, and sees..the same counterpart.

Dust sans is about to kill papyrus for more level. But sans believes he is in deja vu as if he is suffering through memory problems.

He tries to stop his counterpart but dust.. dosent care, as he dosent work for free

Frisk seems their own version on this universe but bad part is, the smile on their own counterparts face.

Rest of them can't do much but watch and unfold the truth, and convince This Universe and Get the man (Or rather Creature) Prunsel into the light.

Dust believes this is a trap, and he'd be killed, and the team reassures it won't happen, as long dust won't stab them first.

Dust agrees but spares his brother, who is injured from the blasters beam

Which begins..The Alliance. The Bait and The Hunt for Prunsel.

(If you'd like to do your version or correct the Undertale Rewind seasons, feel free to view and see them Season 1-5.

I'll also check them out.)