Mordred uses his magic to remove all adults from Earth, leaving only children. Morgaine le Fey uses her magic to turn Superman, Batman, Green Lantern and Wonder Woman into children in order to change things back.
This episode includes examples of:
- Adaptation Distillation: The story is a loose adaptation of the JLA: World Without Grown-ups story, with Young Justice, Shazam and the instigating villain of the story Adapted Out, combined with elements of the Sins of Youth crossover, also with Young Justice, Old Justice and the (different) instigating villain adapted out.
- Adults Are Useless: According to Mordred anyways. However, it's Morgaine le Fey who helps the Justice League get back to Earth to fight him and several children admit out right that they miss their parents.
- Age Without Youth: Once Mordred breaks Morgaine's spell of eternal youth, he ages to the appearance of what you'd expect someone several centuries old would look like. And because he now only has eternal life instead of eternal life and youth, his mother still has to take care of him.
- Agony of the Feet: Superman uses his heat vision on the bottom of an enlarged Mordred's Giant Foot of Stomping, but it doesn't slow him down for long.
- Amulet of Concentrated Awesome: The Amulet of First Magic.
- And I Must Scream: Mordred's fate. As Le Fey states, he had eternal youth, but now he only has eternal life.
- Badass Adorable: The kiddy-fied Superman, Batman, Green Lantern and Etrigan. With Wonder Woman as a Little Miss Badass.
- Batman Gambit: How Batman gets Mordred to defeat himself. He mocks Mordred for being a Momma's Boy, accuses him of liking it and proposes that if he really didn't, he wouldn't allow himself to look like a child forever. Mordred ages himself up. The expected happens.Superboy: Some king.
Wondergirl: I'm not impressed.
Batboy: What'd you expect? He's a boy, doing a man's job.
Mordred: You don't know what it's like, being stuck as a kid!
Batboy: (smirking) Since you got all that power, you could've been a man anytime you wanted! I think you're too chicken to grow up!
Kid Lantern: Yup! Biiiiig chicken, that's what you are!
Batboy: (full-on grinning at this point) Face it, Precious; you like being a little Momma's Boy!
Mordred: I'll show you! I'LL SHOW YOU ALL! (transforms into an adult) I'm older than you now!
Batboy: You sure are.
Mordred: (starts to vanish) What? Wait! NO!!! - Betrayal by Offspring: Morgaine by Mordred.
- Black and Nerdy: John spends some time geeking out about what he can make with his ring.
- Boring, but Practical: When Kid GL was trying to decide what weapon to form to fight the golems, from a laser cannon to a missile launcher, Batboy angrily tells him to just pick something already as the golem was getting closer. He settles with knocking it away with a giant boxing glove.
- Captain Oblivious: Superman.
- The Comedy Drop: the Leaguers are de-aged to face Mordred. When they're restored to their proper ages, Etrigan is in Wonder Woman's arms. He grins at her and facetiously says, "Mommy!"; Wondy drops him like a sack of potatoes on the ground.
- Cool Shades: Green Lantern had bad vision as a child, and needs these, though they take the form of Nerd Glasses until Batman makes a comment about them.
- Creepy Child: Mordred.
- Curb-Stomp Battle: The League just finishes wrapping one up against a gang of C-list villains, consisting of Blockbuster, KGBeast, Cheetah, and Copperhead, before the plot begins.
- Cute Bruiser: Superman.
- Dark Shepherd: How Superman gets some kids to stop fighting and listen to him: he shoots his heat vision at them.
- Did Not Get the Girl: Sadly after a huge amount of Ship Tease, Batman still pushes Wonder Woman away.
- Don't Tell Mama: How Wonder Woman gets the whole populace of children to do what she says or else.
- Double Meaning: At the end of the episode, with everything back to normal. Wonder Woman admits it was fun being a kid again. Batman claims he hasn't "been a kid since he was 8 years old", no doubt referring to the day his parents were gunned down, thus robbing him of his childhood and making him the man he is today.
- Enemy Mine: Morgaine Le Fay helps the Justice League get back to Earth and defeat Mordred...mainly because he stabbed her in the back when he cast his spell.
- Evil Brit: Mordred. Morgaine le Fay is also evil, but willing to work with her enemies in order to work against her son.
- Fake Shemp: Etrigan’s VA Michael T Weiss didn’t return for this episode, so Etrigan spends most of the episode de-aged into a baby, with grunts provided by Dee Bradley Baker, with his one line of dialogue when returned to normal being an uncredited Kevin Conroy.
- Four-Temperament Ensemble: John is sanguine, Diana is choleric, Bruce is melancholic and Clark is phlegmatic.
- Fountain of Youth: The heroes have to accept Morgaine's help to turn them temporarily into children to help them get back to Earth.
- Fun Size: The heroes are turned into kids.
- Genre Blindness: Not that it matters too much. The JL managed to trick Mordred into doing the one thing that will turn his own magic against him: aging himself up.
- Get A Hold Of Yourself Man: Copperhead needs some sense smacked into him by Cheetah when he believes the adults enter Hell.Copperhead: It was Judgement Day! And we got sent to the Bad Place! The Bad Place!!!Cheetah: (smacks Copperhead) Snap out of it, Copper!
- Guile Hero: About the only thing Batman has in child form are his brain and child-sized bat-gadgets.
- Hoist by His Own Petard: Mordred ages himself up to an adult to prove that he can, which causes his magic to send him away to the dimension the rest of the adults are sealed in, among other things.
- Humongous Mecha: Green Lantern makes one.
- Idiot Ball: Mordred aging himself into an adult, allowing him to become Hoist by His Own Petard.
- I Gave My Word: "A bargain is a bargain," in Morgaine's own words, right before she turns the heroes (even Etrigan, her archenemy) back into adults rather than try and take revenge for previously foiling her schemes.
- Imagination-Based Superpower: Aged down, John finds it much easier to use his power ring, but his imagination goes into overdrive and he can't decide what to make first. He is also more easily distracted.
- Immortal Immaturity: Mordred as a side effect of not maturing for centuries.
- Jerk with a Heart of Gold: Bruce's normal personality is softened. He keeps his distance from the other League members as usual, but is the only one who doesn't boss the normal children around (even Clark does!), and he is the first to tell everyone not to hurt Etrigan.
- Kids Are Cruel: Some children have great fun using a guillotine. John briefly ponders using a giant lawn mower to chew up Mordred, and even Clark uses his heat vision to make boys listen to him (although he does aim away from them).
- Little Miss Badass: The aged-down Wonder Woman.
- Living Toys: Mordred animates some action figures to act as his guards.
- Loophole Abuse: Mordred's spell banished all adults to another dimension. How do the League combat him? By having Le Fay temporarily turn them into kids in order to get back to Earth.
- Magic Pants: The heroes' outfits and equipment shrink to fit their smaller bodies, and grow back to normal size at the end.
- Mental Shutdown: After defeating Mordred, he loses his eternal youth, but not his immortality. This leaves him completely unresponsive, trapped in a body that has aged thousands of years in seconds.
- The Mind Is a Plaything of the Body: The de-aged heroes act like eight-year olds… except for Batman, and that is because stopped considering himself a child when his parents were murdered.
- Mistreatment-Induced Betrayal: Morgaine le Fey cooperates with the Justice League after Mordred banishes her.
- Furthermore, given her power to turn the League into children, it's entirely possible that she has the power to undo Mordred's decrepit state at the episode's end, but simply doesn't as punishment for his actions.
- Momma's Boy: Mordred. He does not like being reminded of this.
- My Beloved Smother: Morgaine le Fey.
- Mythology Gag: When John creates his second (much cooler) glasses, they look nearly identical to the mask fellow Lantern Kyle Rayner wears in the comics.
- Not Allowed to Grow Up: Mordred is still a child despite being centuries old. Because if his mother allowed him to age, he'd age forever. Which is why he decides to backstab his mom — he'd gotten fed up with the constant failed plots and wanted to start ruling already.
- Not So Above It All:
- For all their bluster in battle, Blockbuster and Copperhead wind up scared silly when they get transported to another universe. The former is even sucking his thumb!
- Batkid tries to act serious, but being aged down has made him more prone to childish behavior.
- Once Morgaine le Fey restores the heroes to their proper ages, Etrigan calls Diana "Mommy".
- Oh, Crap!: Mordred has this reaction when he realizes he just broke the eternal youth spell, knowing his age will finally catch up to him, but thanks to the eternal life spell, he won't die.
- Only Sane Man: The de-aged Batman is the one who has an easier time keeping his head on his shoulders and focusing on the mission... because of the trauma of his parents' murder that happened at that age.
- Overlord Jr.: Mordred.
- Pet the Dog: There's really no other way to explain why Morgaine would turn Etrigan, her eternal enemy, back into an adult other than this trope, as he wasn't a part of her initial deal to aid the Justice League.
- Plot-Relevant Age-Up: Played straight for Mordred; this allows him to be defeated.
- Puppy Love: Kid Diana's crush on Bruce.
- Sequel Episode: To Season One's "A Knight of Shadows"
, continuing and concluding the Morgan le Fey storyline. - Ship Tease: Between Bruce and Diana, as usual. She also shows a little interest in Clark, though that may have just been an attempt to make Bruce jealous.
- Spanner in the Works: The little redhead girl with the bunny doll. Her justified fearfulness and crying distracts Mordred from killing the Justice Kids.
- Team Mom: Wonder Woman, of the extremely bossy kind.
- Teenage Wasteland: The world becomes this with Mordred's no-adults spell put into place.
- There Are No Adults: Courtesy of Mordred's spell.
- There Is No Kill Like Overkill: Using a guillotine to remove the helmet from an empty suit of armor.
- This Is Gonna Suck: Green Lantern voicing his dislike towards Morgaine's suggestion on how the League will deal with her son.
- Unwitting Instigator of Doom: The girl woke Mordred up just before the heroes could take his Amulet of Concentrated Awesome.
- Victory Is Boring: Briefly implied for Mordred; before the Justice Kids show up, he's trying to act like an "adult" king the best he can, grudgingly using his magic to grant the wishes of any kid that approaches his throne.
- Villainous Breakdown: Mordred loses control of his authority of an adult-free world, especially when the League shows up.
- Wise Beyond Their Years: All four Justice League members are technically this, as they have the physical bodies of their child years with the memories of their adulthood. But they also have their childhood personalities.
