This is how back on Planet Mixel goes in Flain's Mixel Rock & Roll Adventure.
[Meanwhile at Mixopolis]
Delivery Mixel: Hey guys, Special delivery, Where do you want all these books from Optimus Prime?
Flain: The library. Third door on the left.
Delivery Mixel: Even this book that's glowing and vibrating?
[the book flies out of the bag and lands in front of Flain. It's pages flip through to Mal's message]
Lunk: What is it, Flain?
Flain: It looks like a message to Optimus Prime from my friends at Canterlot High.
Magnifo: How is that even possible?
Flain: I have no idea, but it... sounds like they need my help.
[He finds a Mystic 3 sirens book]
Alphablock N: So, that is a book of Sirens.
Flain: That's right, The way Mal described them, I think these new guys sound an awful lot like... the sirens.
Alphablock D: Yikes.
Zaptor: Not the sirens! [whispering loudly to Lunk] I don't actually know what that is!
Alphablock E: Tell me about it.
Flain: The sirens were three beautiful but mystic creatures who had the power to charm everyone with their music. But to maintain this power, they had to feed on the negativity and distrust of others. The more of this negative energy they consumed, the stronger their voices became, and the farther they could spread their dark magic.
Lunk: I don't think I like this story very much.
Flain: If the sirens had their way, they would have divided and conquered all of the world. But a certain Star Swirl the Bearded wasn't having it. Rumor has it he found a way to banish them to another world – one where he believed their magic power would be lost. That world must have been the one where my Canterlot High friends live.
Alphablock H: That's awful.
Krader: But Star Swirl must have sent them there ages ago. How come they're just surfacin' now?
Flain: I don't know. But if my hunch is right and it is the sirens who have come to Canterlot High, this spell they've cast is just the beginning. My friends need me. I have to get back to them.
Alphablock C: Count me in.
Seismo: I hate to burst your bubble, Flain, but the connection between their world and Planet mixel will still be totally cut off for a super long time.
Alphablock S: Yep.
Teslo: Okay, first of all, if there was bubble-blowing going on, why wasn't I told about it?! And secondly, if the connection is totally cut off, how was Mal able to get a message to Flain?
Flain: [gasps] Teslo, you're a genius!
Alphablock D: He is?
Flain: That's right!
Zaptor: Yeah, I get that a lot. [to Gobba] Now about those bubbles...
[They create a Gateway machine portal and successful complete]
Alphablock I: Wow, that's cool.
Flain: ...And the interval between the two points is defined as the square root of the sum of the squares of the separation between the points along three spatial dimensions.
Vulk: Say what now?
Mike: The gateway machine portal, you know that.
Teslo: Duh! He's gonna take the magic in here and put it in there. That'll make the portal open up so that whenever he wants to, he can go from here to there. There to here. Here to there. Here there! Here there! Here—
Seismo: We get the idea!
Flain: Now to see if it actually works.
[He turns it on and the portal's opens and works]
Teslo: Don't suppose we could join you this time around?
Flain: Better not. It could make things pretty confusing if Canterlot High all of a sudden had four of all of you.
Main cast: [Agreeing]
Mike: We can go to!
Vulk: I'm coming too!
Zorch: Yeah, I'm with ya!
Mike: Then let's do it!
Flain: We won't be gone long.
Lunk: Oh, you be careful,
Gobba: Take care!
Krader: Y'all be safe now.
Magnifo: And good luck with that.
Flain: Vulk, Zorch, Mike, you three ready?
Zorch: Count us in!
Vulk: Then let's rock!
[As Flain, Vulk, Zorch and Mike goes into the Portal to Canterlot High]