This is a MotU/Batman crossover. Picture the bat characters as they were in the 1990s Animated Series. It's short and sweet.
At Whispering Woods, Adam, Adora, Teela, Orko, Bow, and Glimmer discuss recent events.
Adam: How Skeletor and Hordak were able to work together is a big question.
Adora: Those two have tried to destroy each other ever since I left the Horde.
Teela: Skeletor's army alone is tough enough. I just hope that some day, he will give up.
Bow: I'm not from Eternia, nor do I pretend to know Skeletor that well, but I don't think he will rest until he's conquered the planet.
Adam: Skeletor always thinks he has the right tools to defeat us.
Adora: I'm certain that as soon as the rebellion frees Etheria from the Horde, Skeletor may take the hint.
Meanwhile, at the Fright Zone...
Hordak: Shadow Weaver, have you found any villains in the universe who may be able to help me defeat the rebels?
Shadow Weaver: Yes, and he happens to be on Earth. My magic tells me that he is confined in some prison called Arkham Asylum, right outside of Gotham City. He is pretty crazy, but his jokes have spelled harm for people.
Hordak: Is there a way we can get him to Etheria?
Shadow Weaver: Leave it to my magic, Hordak.
Meanwhile, at Arkham Asylum, the Joker is sitting in his cell in a straight jacket.
Joker: Batman is always ruining my plans. I have to find a way to rid myself of that pesky bat.
Suddenly, Shadow Weaver's voice comes into the cell...
Shadow Weaver: Joker, come. I am going to open a portal, I want you to come through it.
Joker: How do I know this isn't one of Commissioner Gordon's tricks, testing to see if I'll escape?
Shadow Weaver: Just move it! We have no time to waste!
Joker: Fine, but if you pull anything funny, you will be sorry.
A portal opens in the Joker's cell, he walks through it, it leads to the Fright Zone.
Hordak: Welcome to Etheria, Joker! I am Hordak, and this is my army of men who work for me. I am the ruler of this planet.
Joker: A villain, ruling a planet? Neat. Never happens on Earth, thanks to the likes of the Justice League.
One of the troopers shoots Joker with what is usually a stun cannon, but it just sets him free of the straight jacket and he is in his normal wear.
Hordak: I've summoned you because I thought you may be able to help. I've been trying to rid myself of a group that has been trying to overthrow the Horde, known as the Great Rebellion.
Joker: If I help you, what is in it for me?
Hordak: The Rebels have tried to make me their prisoner, but they've failed. I will tell you what you need to know to stay out of prison.
Joker: Sounds good to me!
Meanwhile, back at Whispering Woods....
Glimmer: I still remember the time She-Ra and He-Man defeated an indestructable ship that Hordak borrowed from Horde Prime.
Adora: That thing was a pretty strong ship.
Teela: Guys, I hate to interrupt, but Madam Razz is on her way.
Madam crashes into a tree.
Adam: Who didn't see that coming?
Orko: Are you alright, Madam?
Madam: Yes. Now, I wanted to warn you about the Horde's newest plot.
Broom: Pretty creepy, if you ask me.
Madam: Shadow Weaver has somehow formed a link between Etheria and Earth, and she has brought a criminal from Earth here to help the Horde defeat us.
Bow: Who is this criminal?
Madam: He goes by the name Joker. From the sounds of it, he is crazy enough to do anything.
Adam: If someone like that is working with the Horde, there isn't a moment to lose.
Adora: Bow, you, Glimmer, and Teela go to the other side of the woods. Orko, Madam, Kowl, you come with us.
After they leave, Adam and Adora transform to He-Man and She-Ra.
He-Man: I think we should contact the Sorceress and try to find out more about this Joker. If anyone would know, it would be her.
She-Ra contacts the Sorceress
Sorceress: Hello there She-Ra. What can I do for you?
She-Ra: Hordak has brought a villain from Earth named Joker.
Sorceress: Oh no. The Joker. He's very dangerous.
Sorceress explains his history
He-Man: So falling into acid put a permanent smile on his face. Sounds scary.
Sorceress: I do know of one man who could help you. He is the man who always helps the Gotham City Police with taking care of the Joker and many others. I must, however, keep his true identity a secret, even from you two. I will contact him immediately.
She-Ra: Thank you, Sorceress.
Meanwhile, back on Earth, at Wayne Manor...
Alfred: Things seem quiet around here lately, Master Bruce.
Bruce: I'm still keeping my ears open.
Suddenly, a gate opens.
Tim walks in
The Sorceress' voice comes through the gate.
Sorceress: Bruce, you must become Batman and come through this gate. It is very urgent.
Tim: Can we trust this person.
Bruce: I don't know. But I do know this, I'll need you, ****, and Barbara to keep an eye on things in Gotham while I'm gone.
Tim: Sure thing, Bruce.
A few minutes later, Bruce is changed to Batman. He comes back up and walks through the portal. Batman then finds himself at an unfamiliar castle.
Batman: What is this place? It seems more eerie than the Batcave.
Sorceress: Batman, you are on the planet Eternia, and you are at Castle Grayskull. I'm gonna need to send you to Etheria, you are needed there.
Batman: What's going on?
Sorceress: One of your enemies, the Joker, has been busted out of prison by a man named Hordak, leader of a group on Etheria called the Horde. If those two do attack, they will be dangerous together. You will have the help of She-Ra and He-Man, two very powerful warriors.
Batman then proceeds through the portal.
Teela: When is this help going to arrive?
The portal suddenly opens.
He-Man: I think it's here now.
Batman walks out of the portal
Batman: So, I hear the Joker is on this planet.
She-Ra: Yes, and he has joined forces with Hordak. We must stop them.
Batman: Lead the way.
Awhile later, He-Man and She-Ra are approaching the Fright Zone on Swift Wind. Batman arrives, seeing Grizzlor standing outside. Batman goes towards him.
Grizzlor: What the...
Batman: Where is he?
Grizzlor: Where's who?
Batman: You know who I'm talking about!
Batman punches Grizzlor in the face.
Grizzlor: Honestly, I don't know who you're talking about?
Joker comes walking out
Joker: DRAT! It's Batman!
He-Man: And he's not alone, either!
Joker: When did Robin and Batgirl change their appearance?
Hordak walks outside
Hordak: She-Ra and He-Man! But who is this mysterious guy, Joker!
Batman: My name is Batman, and I assume you're Hordak.
Hordak's arm turns into a cannon, he shoots it, Batman does some tumbles behind some rocks.
Hordak: Where did he go?
Joker: I wish I knew he was coming, I would've warned you about how slick he is.
She-Ra: What brings you two together, anyway?
Hordak: The Joker here is my ticket to defeating you and the rebellion, She-Ra.
He-Man: You're gonna need more than him to beat us.
Hordak: Troopers, get them!
Batman uppercuts some troopers, She-Ra and He-Man throw them around.
Batman: Ready to give up yet?
Hordak: Not a chance.
Joker tries to shoot acid out of the flower on his pink tuxedo, it misses and hits a trooper.
Hordak: You fool! I'll have to take care of him, it seems.
Hordak turns into a rocket, then goes over to confront Batman. Meanwhile, Leech, Mantenna, Catra, Scorpia, and Modulok are keeping He-Man and She-Ra busy.
Batman: I can see you're impossible to deal with.
Batman throws a batarang, but Hordak uses his arm cannon to melt it.
Hordak: Nice try, Bat breath.
The Joker goes over and tries to use his zapper on She-Ra, but she ducks, and it hits Catra.
Batman now has Hordak tied up, but Hordak becomes a rocket and escapes. He then joins He-Man and She-Ra in taking out the rebels. Joker tries to run for higher ground, but Swift Wind deliberately flies into him, knocking him down. Batman grabs him.
Batman: Back to Arkham for you, Joker.
The rest of the Horde retreats back into the Fright Zone. Awhile later, back at Whispering Woods...
Orko: I wonder how Batman is making out with bringing the Joker back to prison.
Adora: I'm pretty sure Joker is tied up at the moment.
Adam, Adora, Orko, Teela, Bow, Glimmer, Kowl, Madam, and Broom laugh. Meanwhile, back on Earth, at Arkham...
Joker: BATMAN, YOU WON'T GET AWAY WITH THIS! WHEN I ESCAPE AGAIN, I WILL CRUSH YOU! HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA !