After Earth is attacked by a Gordanian battleship, the Justice League is aided by an army of hawkmen from Hawkgirl's home planet of Thanagar. The Thanagarians offer to help Earth build a shield to defend against the Gordanians, but Batman discovers that this is just a ruse. Hawkgirl finds herself torn between her allegiance to Thanagar and her commitment to the League, as well as between her betrothal to the Thanagarian commander Hro Talak and her deep budding romantic love for Green Lantern, John Stewart.
- Ascended Extra: Kragger in the comics was an ordinary member of the Wingmen Corps with Katar Hol who died fairly early in the first issue he debuted in. Here, he's The Dragon to Hro Talak and even makes an appearance later in the series.
- Adaptational Villainy: While the Thanagarians in the comics have at times been portrayed as The Empire, they more or less kept their conquests away from Earth. Katar Hol in particular has always been an anti-hero at his worst where Hro Talak is perfectly willing to murder billions to protect his people. Then again, he's not the show's true adaptation of Katar Hol.
- Admiring the Abomination: Batman is admittedly impressed by the Hyperspace Bypass. Superman's more interested in just wrecking it.
- Any Last Words?: Hro to John. John's response? "Yeah. You can kiss my axe!"
- Aliens Are Bastards/Smug Supers/Superior Species: The Thanagarians don't see much of humans - considering them to be a weak, primitive people - (the last bit is all the more interesting given their own culture), and use them as slave labour for the hyperspace bypass. They don't even think much of the Justice League at first having captured them (largely thanks to Shayera's intelligence on their abilities) - one of them openly expresses doubt that any of them, even the Martian amongst them, could understand how the properties of Nth metal works; and even the protests from one of their own to stop the project as it will kill billions of lives is met with accusations of disloyalty to Thanagar.
- Alien Invasion: The Thanagarians plant the fear of a Gordanian invasion as a False Flag Operation and pose as benevolent defenders while hiding their true purpose, which is more or less use Earth as a salient in a long-distance attack on the Gordanian homeworld, which will destroy Earth of course, but that's not their problem.
- Alien Autopsy: Batman's analysis on a dead Gordanian taken from the Gordanian ship and finding out that they were long dead before the ship appeared on Earth, which lead to suspicions on the Thanagarians' true motives.
- Against the Setting Sun: Green Lantern and Hawkgirl say their goodbyes against such a backdrop, complete with Hawkgirl flying towards the horizon.
- Ambiguously Gay: Kragger is a little too devoted to Talak and noticeably jealous of Shayera's relationship to him. The trip J'onn takes into his mind is where it is the most blatant, where a statue of Hawkgirl alongside Talak is smashed and replaced with Kragger. Word of Gay confirms it in the DVD commentary.
- And the Adventure Continues:Flash: No Hawkgirl. No Javelin. No Watchtower. What's gonna happen to the League now? Do we all just walk away?
J'onn: No. We rebuild, starting today.
Superman: J'onn's right. Earth still needs us, and we'll never let her down.
- Anti-Climactic Unmasking: When the League minus Hawkgirl are forced on the run from the Thanagarian forces, they duck into a clothing store. Martian Manhunter recommends going incognito as civilians to avoid detection since as they are, they stick out like a sore thumb. Flash is reluctant since it would mean revealing his secret identity to them all. Batman makes the decision for him by revealing he already knows who he is before unmasking himself.Flash: Hold on a second here! What about the whole secret identity thing? I mean, I trust you guys, but I'm not sure I'm ready to-Batman: (points to Flash) Wally West. (points to Superman) Clark Kent. (unmasks himself) Bruce Wayne.Flash: (Beat) Show-off... (unmasks himself)
- Anti-Villain: The Thanagarians are only concerned with winning their war with the even worse Gordanians (according to them that is), a loss of which would mean the deaths of tens of billions of Thanagarians according to Talak. Once the bypass is destroyed, Talak sees no point in continuing the fight and sadly orders a withdrawal.
- Arc Villain: Hro Talak
- Badass Boast: As the Justice League face down thousands of Thanagarians:Wonder Woman: Pretty bad odds...
Superman: Yeah. They don't stand a chance.
- Bat Scare: When the Thanagarians invade the Batcave, Batman sets this trope on them.
- Benevolent Alien Invasion: The Thanagarians pretended to be this to cover their true purpose, but Batman exposed them in short order.
- Big Badass Battle Sequence: The fight between the League and thousands of fighters of the Thanagarian Expeditionary Force.
- Bittersweet Ending: Earth is saved from destruction...at the cost of their home base, one of their members leaving (breaking up the series' Official Couple), and an untold amount of the Thanagarians threatening the planet. Sweetened a bit by its continuation, Justice League Unlimited, which shows that things can be rebuilt, but even then there's a note of bitterness lingering throughout the series.
- Blatant Lies: Hro punched Kragger right after he says he hated to be the one to tell him of Shayera's treason. Hro likely knows he's lying since Kragger has always been suspicious about Shayera from the start and wouldn't drop it (see Selective Obliviousness).
- Bring It: After the Hawkmen break into the Batcave.John: All through hidin'. Come and get some.
- Captain Obvious: Flash after seeing the stuffed T. rex in the Batcave:Flash: That's a giant dinosaur!
Alfred: And I thought Batman was the detective.
- Catch a Falling Star: Batman is pulled out of the collapsing wreckage of the Watchtower by Superman seconds before impact.
- Chronic Hero Syndrome:
- Superman abandons the big fight in order to go save Batman's life during the Colony Drop.Superman: Always have to be the hero, don't you?
Batman: Right back at you.
- Batman being the one to do the Colony Drop at all is hero syndrome on his part. J'onn could've easily done most of the piloting, then simply phased out of the ship as it got close, without putting himself at risk at all.
- While in civilian guise, Wonder Woman and Batman see the Thanagarians accosting some civilians. Diana wants to jump in and give them what for, but Batman stops her. Then, they have to step in anyway when said accosting leads to a building collapse.
- Superman abandons the big fight in order to go save Batman's life during the Colony Drop.
- Colony Drop: Batman maneuvers the Watchtower to crash into the Thanagarians' hyperspace bypass.
- Conflicting Loyalty: Hawkgirl as soon as she finds out that the Thanagarians are actually building a hyperspace bypass on Earth, starts having second thoughts on serving them, and eventually assists the Justice League in stopping them. She invokes this trope at the end, and resigns before hearing the League's verdict, feeling that she didn't want to divide the League further than she already did by making them take a position on whether to keep her or not.
- Contrived Coincidence: The prison ship departed from the Gobi desert. When League make their Great Escape the ship was conveniently flying over Metropolis.
- Curb-Stomp Battle:
- In Part 1, the Thanagarians deliver one to the League due to knowing their weaknesses.
- The League returns the favor in Part 3's Batcave fight.
- Deadly Dodging: John goads Talak into attacking him while he has his back to a forcefield, then dodges. Talak electrocutes himself and destroys the field protecting the vital switch.
- Death Glare: Wonder Woman, still bitter about Shayera's betrayal, has a very unamused look across her face when the erstwhile Hawkgirl gives the speech announcing her resignation.
- Death Seeker: The DVD commentary points out this is the second time this season that Batman purposely pulls a move that might get him killed to take out the threat, personally piloting the Watchtower to land on the bypass.
- Deep Cover Agent: Hawkgirl. Though she justified her actions because she thought she was helping Thanagar in a way that wouldn't involve hurting Earth. She defected when she learned that Earth would be destroyed in the process.
- Description Cut: During the peace summit at the beginning, J'onn thinks that terrorists may have already infiltrated the meeting, but Batman assured the League he's "got it covered". We next see Clark Kent inside as one of the press.
- Domestic Abuse: Hro Talak turns abusive toward Shayera Hol when she turns against him in the latter part of the story.
- Dramatic Unmask: While arguing with Shayera, Hro removes his helmet to reveal his handsome face has been scarred from when he was in an enemy prison camp.
- Easily Forgiven: Flash vocally defends Hawkgirl when the team is debating whether to expel her, and he gives her a goodbye hug when she announces her resignation.
- The End of the World as We Know It: The hyperspace bypass that will destroy the Earth.
- Everyone Can See It: John and Shayera, courtesy of the rest of the League, except Flash.
- Expy: Hro Talak is basically Hawkman But Evil; his name is even an anagram of "Katar Hol". According to the DVD commentary, the writers were seriously considering having him actually be Hawkman; but DC vetoed the idea of making Hawkman a genuine villain and the writers ultimately agreed (and did eventually introduce a more conventionally heroic Hawkman in a later season).
- Fake Out Makeout: Bruce and Diana in the Indian restaurant. Neither seems to mind the opportunity.
- Gosh Dang It to Heck!: Green Lantern's fight with Talak.Hro Talak: I've beaten you, little man. Any last words?
Green Lantern: Yeah. You can kiss my axe.
- The DVD commentary reveals that the writers were split on whether they liked the line or thought it was silly. Bruce Timm broke the tie.
- Greater-Scope Villain: Two sets of them, and in a rare example of this trope are directly opposed to one another: the Gordanians, enemies of Thanagar, and the Thanagarian War council, who Hro answers to.
- Grey-and-Gray Morality: The Thanagarians plan to build and activate the hyperspace bypass at the cost of destroying Earth in the process. Though they acknowledge this as a necessary evil and take no pleasure in this task, at the same time, they look down on humanity as primitives whom they dont put much value on, they are not impressed with the Martian and Kryptonian either. The Justice League manage to save Earth; unfortunately, this action inevitably dooms the Thanagarian civilization to being conquered by the Gordanians, though considering how the Thanagarians would have sacrificed Earth and its inhabitants, humanity cant really be blamed for defending themselves or accepting the Thanagarian's account of their conflict with the Gordanians.
- Handy Cuffs: Batman's hands are tied behind his back, but he fixes this mid-escape. John's hands are bound in front of him, and one of the first things he does is bludgeon a guard with his restraints.
- Heroic Sacrifice: Batman intends to do this but is saved by Superman.
- I Like Those Odds: Superman, Wonder Woman and Green Lantern are heading straight for the Thanagarian mothership (and the dozens of smaller ships around it).Wonder Woman: Pretty bad odds.
Superman: Yeah, they don't stand a chance.
- If You're So Evil, Eat This Kitten: One of Talak's lieutenants boasts about how easy it was to capture the League with the information Shayera provided the Thanagarian fleet on them. When Shayera still warns him not to underestimate them, he interestingly concedes and suggests that they be eliminated while they are still weak before they can become a serious problem, even giving Shayera the blaster to do it. Shayera in response points out that the mission was to construct the bypass and capture the League, nothing more (though she also points out that killing Earth's heroes will alienate the human populace, causing them to rebel). This gives the lieutenant the first hint that Shayera's loyalty to Thanagar is wavering.
- Informed Flaw: The episode reveals Jonn cant read the minds of Thanagarians (at least not easily), something thats never been brought up the entire show despite Hawkgirl being a member of the team for the entire series up to this point. This is slightly hinted at earlier in "Only a Dream", where J'onn couldn't get into Hawkgirl's mind to save her from Doctor Destiny.
- Immunity Attrition: The Thanagarians are initially immune to J'onn's power. (It's what clues Batman into thinking the Thanagarians are up to something.) Until the situation is critical enough for him to try harder.
- Ironic Echo: In Part 1, Shayera manages to talk John down from fighting her after the League realizes the Thanagarians are betraying them, only to sucker slug him with her mace. Similarly in Part 3, Shayera fights Talak while begging him to find another way to defeat the Gordanians without sacrificing the Earth; he seemingly relents only to slam and electrocute her with his battle axe.
- It Has Been an Honor: Batman to Flash and J'onn before making his planned sacrifice.
- It's Personal: Hro takes Shayeras relationship with John very badly to the point that hes willing to hand wave her committing treason against Thanagar if she tells him that her relationship with John didnt mean anything. After she doesnt, Hro spends the rest of the episode abusive and vindictive, snapping out of it only when the bypass is destroyed.
- It's Raining Men: The Thanagarian army descending from the sky. Considering they are all Winged Humanoid, it produces a surprisingly biblical image.
- Kick the Dog: Shayera smacks John with her mace during the first fight between the League and the Thanagarians. He brings it up in the Batcave later.
- Know When to Fold 'Em: There was no Last Villain Stand. After the League destroy the hyperspace bypass Hro decides to give up and withdraw his forces from Earth.
- Let's Split Up, Gang!: Justified; once they change into civilian clothes, the Justice League split up because the Thanagarians will be looking for a group of six people.
- A Million Is a Statistic: Shayera/Hawkgirl balks at hearing Talak's plans for Earth: to use it as the last chain of an Hyperspace Bypass, which would inevitably destroy it, and sacrifice billions. Talak points out that Thanagar's people number in the tens of billions and uses this as justification to go forward with the plan. He also believes that her attraction to Green Lantern is specifically why she's objecting to the plan, and not the deaths of the billions from the Earth's destruction, though considering the fact that he lied to Shayera the whole time and delayed telling her the truth, it's likely he's just projecting to hide his moral squalor.
- Mind Rape: J'onn inflicts one on one of Talak's generals, leaving the latter in a vegetative state. He generally avoids doing this since it involves using a stronger version of his telepathy, but the situation is so dire that he decides to try harder.
- Mythology Gag: Batman dispatches the Thanagarians in the Batcave in the same manner as Brandans cops in Batman: Year One.
- A Nazi by Any Other Name: The Hyperspace Bypass construction has swastika-like lines around it.
- Not So Different: J'onn is one of the more forgiving members of the League towards Shayera, and it's implied that this is because he empathizes with her now being alone in the world.J'onn: She's a pariah to her people. We're all she has left.
- Nothing Personal: Hawkgirl re sucker-slugging her boyfriend. GL of course takes it entirely the other way.
- Offscreen Moment of Awesome: The Unlimited episode "Hunter's Moon" reveals that it wasn't just the supers in the Justice League who are fighting against the Thanagarian invasion. Vixen and Vigilante (and possibly the rest of the future extended members of the League) mention that they were also fighting back, but it wasn't shown.
- The Only One Allowed to Defeat You: When John gets into the Thanagarian ship and is on his way to destroy the shield, several soldiers prepare to confront him.Talak: Belay that! Green Lantern's mine.
- Overly Narrow Superlative: When Thanagarian troops enter an Indian restaurant in search of Batman and Wonder Woman, they ask the owner for "a couple with dark hair." Pointing around the room (where almost everyone present has black hair), the man replies, "could you be a bit more specific?"
- Pet the Dog: Hro saves a goat from being run over in contrast to Flash noting he doesnt like him.
- Plot-Demanded Manual Mode: Batman decides to Colony Drop the League's orbital station, the Watchtower, onto the Thanagarians main base on Earth. Because the Watchtower isn't actually designed for this thing, he is "forced" to stay behind after everyone else evacuated to manually guide the descent until he passes out from the heat. He is pried out of his seat in the last second by Superman. Why he didn't just have J'onn do it, since J'onn could phase out of it, is never explained.
- Propaganda Machine: The Thanagarians take control of the Earth's satellites and begin announcing their occupation of Earth, telling them that they're "helping" them from the Gordanian threat, and trying to pit Earth's citizens against the League for resisting their occupation.
- Properly Paranoid: Batman senses the Thanagarians aren't being entirely truthful about their intentions early on, and sure enough, he's right.
- Reality Ensues: When J'onn gets into a Thanagarian ship and takes a look at the controls, he comes to the conclusion that he has no idea how to drive it. The Thanagarians are just as alien to him as they are to humans after all.
- Reformed, but Rejected:
- By episode's end, when the remaining six League members discuss Hawkgirl's fate, it's clear that Wonder Woman hasn't forgiven Shayera and may never do so. This remains even she returns to the team until Shayera aids Wonder Woman during a trip through the Underworld.
- We can infer that Batman also voted to dismiss her, given that John recused himself, Wally and J'onn took Shayera's side during the debate, and Superman broke the tie in Hawkgirl's favor.
- As far as non-Leaguers go, Alfred is clear in his empathy to Shayera, but the general public would be divided for quite some time to come.
- Secret Identity: Taken for a spin. Pursued by the conquering Thanagarians, the Justice League members decide the safest way to move is in their civilian identities (for the members who have them). The Flash balks at the idea, since it's, you know, his secret identity, and it's not like he doesn't trust the others, but...impatient, Batman simply rattles off everyone's real name, finishing with his own.
- Secret Secret-Keeper: Batman reveals he already knew the identities of the League.
- Selective Obliviousness: Kragger proposes to Hro that they mind-scan Shayera when he believes living on Earth compromised her, but Hro refuses to put his fiancé through that. Even when it's becoming clear to him that she has feelings for John and is against destroying Earth, he doesn't want to believe his beloved would be a traitor. But only when Kragger exposed her to Hro and other Thanagarians for aiding the Justice League, was Hro forced to have her arrested and placed into custody.
- Shoot the Dog: Hawkgirl helps the Thanagarian invasion force defeat the League and conquer the Earth, because she believed the occupation of Earth was necessary to defeat the Gordanians, which was in the best interests of both her home planet Thanagar and Earth. (Though she draws the line at destroying Earth to save Thanagar, and she turns on her brethren upon discovering that they intend to do exactly that.)
- The hyperspace bypass scheme the Thanagarians are using is one to The Hitchhiker's Guide to the Galaxy.
- The storyline borrows some elements from the "Tower of Babel" story, later adapted into Justice League: Doom. The book's plotpoint about Batman betraying the League's trust and using countermeasures against them is transferred to Hawkgirl, and the final scene of the League debating whether to let Hawkgirl stay or go, and Shayera making the decision for them, comes from the final scene of that comic.
- Kragger's homoerotic subtext in regards to Talak is a homage to a similar henchman played by Martin Landau in North By Northwest.
- Shut Up, Kirk!:Shayera: This war is no excuse to—
Hro: I am your commanding officer! You will not question me!
Shayera: I don't even know you anymore.
- Significant Anagram: the Arc Villain's name is an anagram of the Silver Age Hawkman's identity.
- Someone Has to Die: Batman realizes that dropping the Watchtower on the Thanagarian hyperspace bypass will require manual steering, since the station would otherwise miss the target. Instead of telling this to Flash and J'onn, he jettisons them in an escape pod and takes over the controls himself. He doesn't die, as he is bailed out by Superman just moments before the impact.
- Star-Crossed Lovers: The fate of the relationship of the Green Lantern and Hawkgirl. Though really, it could have been called "Planetcrossed" just as easily.
- Suspect Is Hatless: When Bruce and Diana duck into a restaurant to hide from Hawk soldiers, said soldiers come in and ask if a dark-haired man and woman had recently come in. The restauranteur, who is Indian, along with all of his staff and most of his patrons, asks if they could be more specific.
- Tragic Villain: Hro Talak may be an enemy of Earth and the Justice League, but on Thanagar, he is possibly its greatest hero, in addition to being Shayera's fiancee. He sacrificed a lot as part of the war against the Gordanians, and was even captured and tortured by them for years before breaking free. This is implied to be why he was so deadset in making sure the Hyperspace Bypass plan works, even if he had to sacrifice Earth to do it. Shayera's comments suggest that at some point, he changed from the man she knew, to the man the audience saw. In the end, his uncompromising stance on putting the Earth in the crossfire in the war against the Gordanians, pushes Shayera away from him, and he is further incensed when he comes to know about her attraction to Green Lantern, to the point that every plead Shayera makes to spare Earth is interpreted as her saying she loves Green Lantern more, which eventually brings them into conflict, and eventually with Shayera. In the end, the hyperspace bypass is destroyed by the League and he is defeated by Green Lantern. Broken, he surrenders and orders his army to leave. Had he not allowed his experiences in the war to cloud his judgement, he may have found a third option in the war (like say, requesting the League's help in fighting it) and Shayera would have remained at his side.
- Trash the Set: After being the League's headquarters through the series, the Watchtower is destroyed when Batman drops it on the Thanagarians' bypass generator.
- Underestimating Badassery: Before the turn, Jonn asks Paran how the shield generator is supposed to work. Paran brushes off his questions by stating its far beyond his comprehension, assuming Thanagarian tech to be too complicated for a Martian. When Jonn demonstrates he already holds a pretty good grasp of how some of it works, Paran glares, both annoyed that Jonn threw her ego back into her face and probably concerned Jonn will figure out its not a shield generator at all.
- The Thanagarians believe John will be useless without his ring, apparently unaware hes still a badass Marine whos been in situations without his ring before. This bites Hro in the ass especially hard.
- The Unreveal: The outcome of the League's vote on Shayera's dismissal. However, Flash, Wonder Woman, and Superman's votes are either easily inferred or clearly stated, as was Jon's non-vote. This only leaves the knowledge that Batman and J'onn voted opposite ways, though their votes can somewhat be inferred, as well.
- Unwitting Pawn: The League get fooled into helping the Thanagarians until Batman learns the truth.
- Vichy Earth: What occurs by Part II. A particularly harsh example as the Thanagarians intend to destroy it after leaving. Learning this actually makes Hawkgirl turn on them.
- Was It All a Lie?: Green Lantern asks this of Hawkgirl at the end of the three-parter. Hawkgirl replies, "I love you John. I never lied about that", and flies off to parts unknown.
- Washington D.C. Invasion: The beginning of the episode where the League were staking out at a world conference held in Washington in anticipation of a terrorist incident, but only to be interrupted by a Gordanian ship.
- We Need a Distraction: Superman provides one when the League decides to dress up in civilian clothes, split up into pairs and rendezvous over at Wayne Manor. Green Lantern and Flash get stopped at a train station by Thanagarians who are growing suspicious, but Superman (as Clark) decides to go over and pretend interview them with J'onn posing as a cameraman, allowing Green Lantern and Flash a chance to slip past.
- Wham Episode: A major turning point for the series.
- Hawkgirl is revealed to have been a spy for Thanagar the entire time and initially sides with her people over the League when push comes to shove. This betrayal leads to half the League unsure if they can trust her (Wonder Woman especially feels betrayed) and Hawkgirl resigns in shame.
- The fledgling John/Shayera relationship falls apart due to this revelation and the discovery that she was betrothed to Hro Talak the whole time. By series end, the relationship is still broken.
- Thanagar is revealed to be a morally gray empire that sees other races (including humans and Martians) as inferior and expendable. Their actions give the earth as a whole a reason to distrust Thanagarians (and Hawkgirl especially).
- The Thanagarian War leaves the Justice League without the Javelin or the Watchtower. The League resolves to rebuild and expand, setting the stage for the dozens-strong organization next season. The invasion also battle-hardens the team who begins to operate more like a military organization going forward with established hierarchy, support crews, and (most significantly) an orbital laser specifically created to prevent having to drop another Watchtower onto a target. This specifically comes to a head during the Cadmus arc when the government starts wondering how far the League will go to enforce their sense of justice on the world.
- Wham Line: When Wonder Woman watches Batman peform an autopsy on the pilot of the Gordanian ship:Wonder Woman: You don't know anything about Gordanian physiology.
Batman: No, but I know a frozen liver when I see one.
Wonder Woman: What?
Batman: The crew of this ship was dead long before the Thanagarians shot them down. I think we've been set up.
- What Does This Button Do?: Flash does this to said button in the cockpit of a Thanagarian gunship... and blows a giant hole in the wall of Wayne Manor, almost killing Alfred. Batman immediately rounds on him, snarling "THAT'S. NOT. HELPING."
- Whole Plot Reference: A large number of friendly aliens land, whip up fear of an external threat? They ever-so-helpfully offer the "technology" to defeat that threat, initiate a propaganda campaign against any doubters, and possess a hidden world-ending agenda? You could be talking about V; though the Thanagarians have somewhat different motives, the end result for Earth and humanity would be the same.
- Worth It: Hro punched Kragger out of frustration for his broken relationship with Shayera. Kragger's smile afterwards show he's still proud of himself.
- You're Nothing Without Your Phlebotinum: Kragger comments that Green Lantern is "nothing without his toy", referring to his power ring. He's wrong, naturally; John still pulls his weight during the escape scene, and defeats Hro even after his ring is destroyed by tricking him into slamming his axe into a piece of machinery, electrocuting him into unconsciousness.