Batman starts investigating strange behavior and a terrorist attack on a telescope observation station. When Superman shows up to assist he is incapacitated by what appears to be a telepathic attack. This proves to be the start of an Alien Invasion that has been in preparation for years, and they do not have the manpower to fight back. Superman realizes his telepathic attacks are efforts by J'onn J'onnz, the Martian Manhunter, to contact him. This leads to the origin of the alien invaders, and in short order Wonder Woman, Green Lantern, Flash and Hawkgirl join with them to save the world.
Tropes:
- Adapted Out: As a very loose adaptation of JLA's New World Order, we do not see the Imperium, as the show's stand-in for the White Martians, take on the form of the Hyperclan, ruthless superheroes that are able to win over Earth's hearts and minds for a period of time. The closest we get to this is an Imperium spy taking on the doppelganger form of J. Allen Carter, a trusted public figure, and becoming a major spokesperson that encourages a program of global disarmament to secretly make way for the Imperium to take over.
- Alien Invasion: The episode features one and the Justice League managed to stop it.
- All Men Are Perverts: When splitting up for individual targets, Flash really wanted to go with Wonder Woman. Green Lantern explicitly refused, saying now is not the time for needless distractions.
- Arbitrarily Large Bank Account: When Superman talks of needing a place to serve as advanced warning of another invasion, Batman reveals the Watchtower satellite. Superman wonders how he hid THAT from Wayne Enterprise investors. Batman basically tells him not to worry about it.
- Arc Villain: The Imperium for this three-part pilot.
- Art Evolution: The show as a whole has a new color palette compared to previous shows, largely finding a more middle ground between the pastel colors of STAS and the matte black of TNBA and Batman Beyond.
- Batman and Superman receive all-new character designs, Batman is slightly more-lean and his costume has dark purple highlights while Superman has a broader chest and some additional lines on his face. According to Bruce Timm, originally Justice League was going to just reuse their existing character models from TNBA and STAS. It was Glen Murakami and James Tucker who lobbied to redesign the World's Finest from scratch to help sell this was a new, completely different show.
- The Flash's character model was overhauled from the character's prior appearance during "Speed Demons", largely streamlining his musculature and being a darker red. Likewise, while John Stewart's using the previously-established Green Lantern Corps uniform design from "In Brightest Day", the coloring palette has been slightly tweaked from its STAS debut.
- Big "NO!": This is said by Wonder Woman when Batman appears to die.
- Blood Knight: Wonder Woman and Hawkgirl are most eager and willing to become involved in fighting the Imperium. Superman questions the latter on this, and Hawkgirl replies this is simply a fact of life back on Thanagar.
- Body Horror: The leader of the Imperium snakes a tentacle under the skin of J'onn's face.
- Casanova Wannabe: The Flash immediately puts his arm on Wonder Woman, much to her shock.Flash: Dibs on the Amazon!
- Call-Back:
- Superman calling Batman "Bruce" is due to his knowledge of his identity, which he learned back in the Superman: The Animated Series episode "World's Finest".
- Also, Superman's dialogue about his hard work in earning the people's trust and General Wells' distrust of him can be seen as references to "Legacy". According
to Bruce Timm, the callback was actually originally much more explicit ("We can't entrust the world's security to one man — especially him!") before deciding it would confuse new viewers who had missed STAS. As it is, the final line plays both ways for new and veteran DCAU fans. The former can see this as Wells being a practical military tactician, while the latter can recognize the subtext and source of the General's statements and distrust.
- Call-Forward:
- Batman states that he only joins the League as a part-timer; this fact was first mentioned in the Batman Beyond episode "The Call", which aired a year earlier.
- Batman's redesigned look is another subtle call forward to the Beyond-era Batsuit he and later Terry will use (specifically the cowl's ears and boot heel). Bruce Timm has admitted he was probably subconsciously thinking of Beyond while redesigning Batman.
- Canon Foreigner: The aliens of this three-parter did not come from any comic book. They do, however, share some similarities with the White Martians in being connected to J'onn and having shapeshifting abilities.
- Continuity Nod:
- Batman is still using the redesigned Batwing that debuted during TNBA (and also appeared during the crossovers with STAS).
- The Green Lantern Corps, as represented by John Stewart, is still using the Corpsmen uniforms that debuted on STAS (in "Brightest Day").
- Darkest Hour: Part II ends with the heroes' numbers cut by half (Superman and Hawkgirl are captured while Batman is seemingly trapped then fired at offscreen). And Apocalypse Anarchy is rampant in the streets.
- Dead Person Impersonation: The astronaut J. Allen Carter never made it back to Earth, and one of the shape-shifting aliens impersonates him, and becomes Senator.
- Decoy Damsel: The heroes find the imprisoned Superman and Hawkgirl, only for the latter to reveal themselves as aliens in disguise, springing a trap.
- Didn't See That Coming: Batman learns the hard way that the seeming scientists possess Super-Strength.
- The Dissenter Is Always Right: The senator's plan appears to be popular with everyone except for one military general who protests the idea. It turns out that the senator is actually an invading alien in disguise and the call for disarmament is an attempt to weaken Earth so they cannot defend themselves.
- Distant Prologue: Two years pass between the Cold Open (where the real Carter accidentally releases the Imperium) and the present day.
- Door Jam: Batman is trapped (and apparently killed) when a portal closes before he can follow Wonder Woman and Martian Manhunter.
- Dramatic Irony: Some of the looters during the invasion were part of the anti-nuclear weapons protest earlier.
- Early-Installment Weirdness: This is the only time where the title and credits for the episode are displayed over the intro itself, rather than during the first scene of the episode after the teaser.
- Exact Words: The cliffhanger for Part I: Superman and Batman free J'onn from confinement, and are accosted by military personnel. Superman vouches for his new friend because he believes the Martian will be able to help them with the Alien Invasion. Except the military are intent on keeping him there precisely because J'onn can stop them, because the personnel present are also aliens.
- Everyone Meets Everyone: Some of the Leaguers had worked together before, or knew each other by reputation, but this is their first time together as a full group. Superman is so impressed by what they achieve together that he suggests making it permanent via forming a team.
- Faking the Dead: Batman was thought to have been killed at the end of Part II, but it was actually revealed that J'onn mentally shielded him and allow him to prepare the countermeasure against the Imperium — presumably he read his mind and was thus aware of the plan (including the Weaksauce Weakness of the invaders).
- Five-Episode Pilot: This is a three-parter that tells the formation of the DCAU Justice League.
- Flashback: J'onn explains to the other heroes how Mars was attacked by the Imperium a thousand years ago. The struggle went on for centuries, until the final attack put the Imperium in stasis.
- Foregone Conclusion: The invasion will obviously be stopped and Superman and Batman will both survive into Batman Beyond.
- Foreshadowing:
- The heroes discuss that all the details of the Martian expedition must have been kept under wraps by a government bigwig. At the climax of the episode, it's revealed Senator Carter is a member of the invaders.
- In the climax of Part II, Batman drops the Ion Matrix Crystal before the alien soldiers surrounding him. Before shooting him, the invaders react rather strangely — almost as if they don't know what they're seeing...or can't see Batman. Why becomes clearer in Part III's climax: Because J'onn was mentally shielding Batman so he couldn't be detected by the Imperium. The shielding had just taken effect, hence the soldiers' confusion.
- During the climax of the story, Batman cuts Wonder Woman out of her shackles first, while Hawkgirl releases John. Considering the romantic tension between the two couples for the rest of the series...
- A Form You Are Comfortable With: When the heroes first meet J'onn J'onzz, he is shown in his true martian form. To appeal to them, he adopts a more humanoid appearance, which would become a mainstay for him after joining the league.
- From Bad to Worse: While in the facility where the real scientists are being kept, Batman gets attacked by a rather vicious dog. After getting to the ceiling, Batman sees the dog do a Wall Crawl and transform into its true alien form.
- Gondor Calls for Aid: During the escape from the military installation where he is imprisoned, J'onn telepathically sends a distress call to other heroes, leading to the Seven coming together for the first time.
- Handshake Refusal: Batman refuses to shake hands with J'onn J'onzz because of his distrustful nature.
- Heroic Bystander: At the beginning of Part III, Wonder Woman observes the carnage on the streets by people thinking it's the end of the world, and she ponders if man's world is even worth saving. She was instantly proven wrong in the next scene when a couple of strangers are asking for help to rescue a few kids trapped in the rubble.
- Hoist by His Own Petard:
- Batman somehow changes the ionization on the Power Crystal, turning it against the invaders.
- Flash gets caught in a sticky trap, and later gets a tripod to step in one while attempting a Giant Foot of Stomping, ripping the leg off.
- Hollywood Science:
- The Martian commando team is shown wearing gas masks against the nerve gas. By definition, nerve agents are absorbed through the skin as well as through breathing.
- The invaders' Weaksauce Weakness is sunlight, with Batman claiming that coming from the "depths of space" they have no defense to ultraviolet radiation. While this sounds cool, the truth is that space generally has much more ultraviolet radiation and our atmosphere blocks out the vast majority of it.
- Hostile Terraforming: One of the first things the aliens started doing was drop factories that spew smog into the air. Rather than being toxic, it seems to be for the more practical reason that the aliens are harmed by direct sunlight.
- Ignored Expert: J'onn J'onzz tried to warn humanity of the Imperium's invasion. Instead, the US military shot down his ship, held him captive for who knows how long and refused to listen to him, (though this was because Imperium invaders had already infiltrated the US military). Because of this, Earth almost falls to the invaders.
- It Only Works Once: Justified. After hearing J'onn's story, Flash asks him why he doesn't make another batch of the nerve gas he used the first time he stopped the Imperium. J'onn explains that the gas can only be made from a rare Martian plant, and the only sample he brought with him was destroyed upon his capture.
- Leeroy Jenkins: Flash charges in, ignoring GL's attempt to plan things first. Naturally he gets stuck (literally).
- Monumental Damage: Part 1 begins with The Daily Planet Globe destroyed by the Imperium after they fully invade Metropolis and later on at the episode's ending, they destroy the Eiffel Tower and all of Paris with the tower itself ablaze.
- Mythology Gag:
- Secret Origins was a comic book series that retold the origin stories of DC superheroes.
- The story begins with a man named J. Allen Carter. In the comics, the story of the Justice League arguably begins with the Justice Society, whose founding members included the original Flash, Green Lantern and Hawkman: Jay Garrick, Alan Scott, and Carter Hall.
- The Imperium, being a shapeshifting race of white aliens coming from Mars, are clearly inspired by the White Martians from the comics.
- When Superman suggests forming a team of heroes, the Flash responds, "What, you mean like a bunch of Super Friends?"
- Like in the comics, the Justice League was formed as a result of an alien invasion.
- In spite of his Super-Speed, the Flash is the last to answer J'onn's distress call during Part II, which is a comic-wide Running Gag for the character (specifically Barry Allen, even though later episodes establish it to be Wally West under that mask).
- Once again, the Eiffel Tower is destroyed by alien invaders at the end of part one.
- The entire pilot is a very loose adaptation of Grant Morrison and Howard Porter's inaugural JLA storyline (New World Order), from an alien invasion with links to Martian history to Batman seemingly being killed at the end of the second act.
- Noodle Incident:
- Batman isn't surprised to see Hawkgirl, just to see her at the fight. Superman doesn't ask Green Lantern John Stewart where Green Lantern Kyle Rayner, the Green Lantern he met in his own show is.
- Green Lantern himself is fresh off stopping an uprising near Rigel IX before arriving at the scene.
- Nuclear Option: Discussed and prevented. Superman got the UN to let him dismantle all of the world's nukes...only for the Earth to be immediately invaded by aliens after humans no longer had a Nuclear Option (one of the major supporters for the move was an alien pretending to be human). Later episodes had nuclear weapons, so most likely they rebuilt them to ward off more alien invasions.
- Perception Filter: J'onn making Batman invisible through his mental powers.
- Plot Hole:
- The aliens are burned by sunlight, even those disguised as humans. How could the alien impersonating Carter have come back to Earth and spent two years as a senator without ever stepping foot in sunlight?
- Hawkgirl herself is a retroactive one after the revelations of Season Two and "Starcrossed" in particular. If Shayera's mind was blocked from psychic probes, how was J'onn able to telepathically summon her?
- Pyrrhic Victory: J'onn concludes his flashback by noting how the Imperum was defeated and placed in suspended animation, but at the cost of his entire civilization.
- Remember the New Guy?: Superman, Batman and Flash were already established figures in previous shows, while Wonder Woman and Martian Manhunter get quick origin stories told in tandem with the narrative. Hawkgirl and John Stewart Green Lantern on the other hand get very brief introductions that they were known figures despite not shown before.
- Reverse Polarity: What Batman does to the Power Crystal he got his hands on.
- Seen It All: As J'onn begins explaining the situation, Flash says this is just too weird for him. Green Lantern says it's actually less strange than the things he's encountered in deep space.
- Sequel Hook: The newly formed Justice League managed to send the aliens running, but the possibility they might return is left in the air. These particular aliens don't, but there are other Alien Invasions.
- Shout-Out:
- Apart from all the references to The War of the Worlds, there are a couple to John Carter of Mars. The two astronauts in the beginning are named Ed (As in Edgar Rice Burroughs) and Carter, whom we later find out is named J. Allan Carter (J for John, perhaps?)
- The 'J. Allan' might also double as a nod to famous Ufologist J. Allen Hynek, who worked with the Air Force on Project Blue Book and created the 'Close Encounters' classification system.
- There is also a small one to a certain rival superhero team. Senator Carter mockingly calls the team "Earth's Mightiest Heroes", a term usually reserved for The Avengers.
- Sole Survivor: J'onn J'onz is the last Martian.
- Starter Villain: The aliens.
- Stating the Simple Solution: When the League witnesses the smog cloud being formed by one of the shapeshifter's factories, Flash isn't worried — J'onn can simply create some more nerve gas, right? Unfortunately, the gas could only be created via a Martian plant, and the only sample J'onn had with him was destroyed upon his capture. Flash promptly asks "Uh, what's plan B?"
- Stock Scream: The Wilhelm Scream when J'onn throws an invader off the power core.
- Take That!:
- The entire premise of aliens having Superman destroy nukes so they could invade can be seen as a joke on the concept of Superman IV: The Quest for Peace.
- The alien posing as Carter derisively refers to the captured heroes as "Earth's mightiest heroes" before revealing himself. That's the frequent tagline for the Justice League's marvelous competition.
- Tentacled Terror: The "Imperium" is a very evil, big, night-loving blob with creepy tentacles.
- Theme Music Power-Up: A triumphant piece that plays when the rescue mission begins in Part III. It starts playing again during the climax as the heroes break free of confinement and start turning the tables against the aliens.
- Time Skip: It's presented that an (unspecified) measure of time has passed since "Legacy" as Superman has managed to repair the people's trust in him to some degree (whereas they seemed to near-universally distrust him after the brainwashing incident).
- Tripod Terror: As you'd expect with invaders from Mars. Turns out this makes them vulnerable to being tripped up.
- Unrelated in the Adaptation: The invaders are not native Martians (which explains why they aren't called White Martians at any point); they are as alien to J'onn as he is to everyone else.
- Unwitting Instigator of Doom: Allen Carter the astronaut accidentally putting the three-parter into motion by awakening the aliens from their imprisonment.
- Unwitting Pawn: The alien posing as Carter mocks Superman for being this to the Imperium, saying his good intentions made humanity helpless in the face of invasion.
- We Meet Again: Upon arriving, this is how the Imperium greets J'onn.
- Weakened by the Light: The Imperium has no resistance to sunlight.
- Where Does He Get All Those Wonderful Toys?: Superman asks Batman if his stockholders know about the newly-commissioned Watchtower, which Batman handwaves with it being "a line item, hidden in the Aerospace R&D budget." Sure, that hides the funding, but says nothing about assembly either pre-launch or in orbit. (Although with Superman available, Batman at least wouldn't need a launch vehicle — or if Clark had a spare weekend, a construction crew.)
- Whole-Plot Reference:
- The entire episode is based on The War of the Worlds. Both are about alien invaders from Mars who want to sap the world's resources, both feature tripod crafts that level major cities, and when it seems the aliens have won, they are shown to be easily defeated due to a Weaksauce Weakness set up as a Chekhov's Gun in the first act. There is even a General Wells, and once again the Eiffel Tower is set blaze which is a direct reference to the ending of the 1953 film.
- There's also a Whole Sub-Plot Reference to Superman IV: The Quest for Peace. Superman (recruited by Senator Carter) goes before the United Nations with a plan to personally disarm the world of its nuclear weapons in an attempt at lasting peace. Unlike in the movie, however, it's a trap.
- You Are Not Alone: When J'onn laments that he is the Last of His Kind, Superman sympathizes with him and offers to have Earth as his new home.
