After June got cleaned up from her fight with Jaune, who forgave her BTW, we see June hugging her brother like she used to do when they were young while Marceline was just licking Jaune's neck, but she stopped after seeing how happy June is as she then went to his ear and whispered

Marceline: (whispers) looks like she's very happy to be your sister again, huh?

Jaune was blushing madly & shaking nervously while Marceline is licking his neck

Jaune: (blushing) yeah, i can see that.

He then sees June smirking at him

June: (smirks) I didn't know you became submissive when you met her, hmm?

She said as jaune blushed in embarrassment

Jaune: (blushes) shut up, we're not kids anymore.

Then Simon walked up to her

Simon: hey, June, I've been meaning to ask.... How did all of you get here to find Jaune in the first place?

He asked, making teams RWBY, JNPR, CFVY, and the cotta-arcs widen their eyes in shock, but mostly CFVY & the cotta arcs because they forgot to tell jaune when they reunited with him

June: (giggles embarrassingly) right, forgot to tell you about that.

Nora: well, it's because we used this remote that a scientist named Pietro built.

Then simon walked up to her and grabbed the remote

Simon: huh, interesting. It almost reminds me of Prismo's remote back in his time room, since it does allow it's user to travel to other realities.

Yang: wait, how do you know that?

Everyone just looks at simon, who had a deadpan look

Simon: it's a long stor-OW!!!

He screamed in pain as the remote shook him, started smoking and eventually...

(POOF!!!)

It blew up, much to everyone's sadness

Weiss: THE REMOTE!!!!!

Blake: OH GREAT, NOW WE'RE STUCK HERE!!!!!

Jaune: (Bleep)!!!!!!!!

everyone, even Adrian, stared at him in shock after he bleeped out loud

Simon: ....wow, you got quite a mouth on you, huh Jaune?

Jaune: (rubs neck) sorry, I just didn't know that the remote was gonna break.

He said while he and everyone looked at what's left of the portal device/remote

Coco: well, this is not going to get fixed.

She said as she sees Velvet having sad eyes as her bunny ears folded down

Cardin: well, I'm out of here. Goodbye everyone.

He said as he just walked away

Jake: well, since that remote's broken, why not just we resort to plan B.

Everyone (except finn & the others) just stared at Jake

Ren: what do you mean by ''Plan B''?

Ruby: yeah, what ren said.

Jake: simple (pulls pickle jar out of his stomach) we call prismo for help.

As everyone saw jake stretch the pickle jar out of his stomach, they were shocked as Blake stumbled on the ground and hid behind a tree

June: (wide eyes) how did you do that?!

Jake: I'm magic.....and that I'm also part-shapeshifting-alien, so that's a bonus.

He said as Weiss just fainted and Jake touched the letter ''P'' on the jar, which made everyone disappear

(WITH CARDIN)

We see Cardin walking down the path leading to the forest's exit, then suddenly he just vanished from OOO

(IN PRISMO'S TIME ROOM)

In the time room, we see Prismo & Scarab being all scared & shit after finding out that a certain ''life destroying'' enemy of Finn & Jake's has arrived on remnant, then they see the gang show up as the two acted all calm right now

Prismo: oh hey, Jaune. (looks at Jake) how's it going, my broski?

Jake: great, Prismo.

He said as he and Prismo fist bumped, since they are good friends after all

Jaune: also, just saying this as a reference right now.... How you doin'?

(Joey from ''friends'' reference)

He asked, making June giggle for a bit, even though she has no idea what's that in reference to at all

Scarab: well, Prismo & I were doing alright until we got an alert that a certain enemy that Finn & Jake defeated a bunch of times in the past has arrived on Remnant.

Prismo: you know, a villain whose name starts with.... an ''L'.

As he said that letter, Finn & Jake grew neutral faces at knowing who they're talking about, even Huntress Wizard too since Finn did tell her about who prismo & scarab are talking about

Simon: oh no, not him.

Marceline shook in fear or a bit, same as PB

But as for the ones from Remnant, they had no idea who they're talking about

Jaune: who are you talking about, guys?

Prismo: we're talking about this guy.

He then pulled up an image of, well, you know who Prismo & Scarab are talking about

Ruby, Velvet & Nora screamed in fear while Ren widened his eyes in fear, along with Jaune, Blake, Yang, Weiss, Coco, Yatsu, Fox & Cardin

Adrian was tearing up while Terra & Saphron were hugging their infant son away from the Lich on screen

Phyrra: WHAT IS THAT THING!!??

And then...

Simon: he's called the Lich.

Everyone from remnant stared at Simon in shock

Cardin: you know what that thing is?

Simon nodded

Simon: yes, he's a very powerful enemy of Finn & Jake's they defeated a few times in the past. I even went to a universe where a counterpart of the Lich succeeded in killing all life there. He worships a indecipherable embodiment of chaos named GOLB. Hence the lich's nickname, the last scholar of GOLB.

Marceline: and not only that, simon's love of his life, betty, even sacrificed herself by fusing with GOLB, now she goes by the name ''GOLBetty''.

Jaune: wait, when did that happen, Mar mar?

Marceline: about, like, a few years ago.

.

.

.

.

.

Jaune & others: ....oh.

Then they looked at Prismo & Scarab

June: do you two know a way to kill the Lich?

she asked as Prismo & scarab look at each other and nod at knowing that they have no choice but to tell them about their home's forgotten history

Prismo: well, before we tell you, you're all going to want to sit down.

Scarab: you'll want to know this before you fight against the lich & salem in the future.

they said, which made the gang confused at wondering who this ''Salem'' is

PB: um, who is Salem?

(one LONG history session about remnant's forgotten history, later)

Jaune & June look at each other with angry faces, then back at Prismo & Scarab

Jaune & June: ....F*ck.

Prismo: yeah, I feel ya.

Scarab: anyways, Jaune, here ya go.

He said as Prismo snapped his fingers and materialized a sword, a sword that looks way better than Jaune's old weapon since he knew it was meant for him as he grabbed it and examined it

(this is Jaune's new sword)

June: SO AWESOME!!!!!

She said with stars for eyes and Jaune looked at Prismo & Scarab

Jaune: woah.

He said while smirking and raised his new sword

Prismo: Yep. Also, fun fact, that sword also happens to be an upgraded Crocea Mors.

Scarab: which used to belong to an alterante version of you, but it was buried with the alternate you after you died from some battle or something, i didn't get all the details.

Prismo: now off you go.

he said as he snapped his fingers and pixelated them all

(ON REMNANT, AT BEACON ACADEMY)

we see the gang, along with Marceline & her friends, get pixelated at the beacon courtyard, but good thing no one is around because it's night time right now

Jaune: (deadpan) sh*t, this place is already giving me bad memories right now.