The Justice League reluctantly teams up with the Secret Society to repel Darkseid's full-scale invasion of Earth. As the League and Secret Society members battle the Apokolips fleet across the planet, Superman, Batman, and Lex Luthor take on Darkseid.

!!This episode includes examples of:
* AlienInvasion
* AndTheAdventureContinues: The TropeNamer
* BackForTheFinale: [[spoiler:J'onn]]
* BadassBoast: Darkseid, natch.
-->"I'm more powerful than I've ever been and the last time we met, you barely managed to hold your own."\\
"Super or otherwise, you're merely a man. And I am a god!"
** From Luthor:
-->'''Metron:''' "Only a twelfth-level intellect has a slightest hope of surviving what you are about to experience."
-->'''Luthor:''' "Then I'm over-qualified."
* BetrayalInsurance: when divided into teams, a single Society member was placed outnumbered with a group of Leaguers to curb possibilities of double-cross.
* BookEnds: Batman was the first hero in the DCAU franchise to appear onscreen, and he's the last one seen in this episode. Also, Kevin Conroy had the second line in the first ''BTAS'' episode "On Leather Wings" (as an incidental character) and gets the second-to-last line here.
** Like the first episode of this series, this episode sees the team needing to defeat an alien invasion.
** Within the episode itself, both the beginning and closing shots take place on the Metro Tower.
* [[spoiler:DisneyVillainDeath: Darkseid and Lex Luthor take hold of the Anti-Life Equation and disappear in a flash of light. WordOfGod says they end up in the Source Wall. Darkseid gets better though, as seen in the New 52's ongoing ''Justice League Beyond''.]]
* CallForward: Superman's quip about Batman getting soft in [[WesternAnimation/BatmanBeyond his old age]].
* CurtainCall: Pretty much the entire team running/flying down the steps of the Metro Tower. The groups are broken up into different teams from the comics before concluding with the show's Big 7.
* DidYouJustFlipOffCthulhu: Batman manages to almost knock Darkseid down ''and'' manages to avoid his Omega beams.
* EnemyMine
* ExactlyWhatIAimedAt: Flash and GL hurl one of Darkseid's doomsday devices into the sky. They wanted to throw it to the sun, but the trajectory was "slightly" off...it hit a warship instead.
* FateWorseThanDeath: The Agony Matrix.
-->'''Darkseid:''' Imagine the worst pain you've ever felt in your life, times a thousand. Now imagine that pain continuing forever. Oh, that's right. You don't have to imagine.
* GodzillaThreshold: Darkseid has pressed one too many of Superman's buttons, so Supes finally decides to unleash his full strength.
* GondorCallsForAid
* GrandFinale
* HostileTerraforming: Darkseid's army drops magma towers in order to create fire pits ("Apokolips on Earth" as Steel puts it).
* IronicEcho: "Let's go."
* LawyerFriendlyCameo: one of the effigies in the Source Wall looks suspiciously like {{Galactus}} of the ''Franchise/MarvelUniverse''.
* MegatonPunch: Superman sends Darkseid flying across Metropolis.
* MercyKill: In response to Superman surviving the effects of the Agony Matrix, Darkseid says this:
-->"Still alive. You impress me, Kryptonian. More...your valor has touched my heart. Oh yes, there is still some small part of me that knows mercy. I will end your pain with something special I've been saving for just this occasion. ''(takes out a Kryptonite knife)'' I'm going to carve out your heart and put it on a pike in my throne room."
* MercyLead: When Atomic Skull protests that being arrested is poor repayment for [[EnemyMine the villains' help]], Batman offers them a five-minute head start. When they see that's the best deal they're going to get, they take off (though Giganta takes a moment to give Flash a kiss).
* MonumentalBattle: battles take place near the vicinity of the Eiffel Tower, the Great Wall of China, Big Ben, and the Washington Monument.
* PrecisionFStrike:
--> '''Superman:''' ''(angrily)'' C'mon, it's Lex flippin' Luthor!
* SaveTheVillain: Batman saves Lex after Darkseid blasts him off the top of the Daily Planet building.
* TemptingFate: When Luthor bets that Darkseid won't notice Superman, Batman and himself battling atop of the Daily Planet.
* WorldOfCardboardSpeech: TropeNamer
-->'''Superman:''' That man won't quit as long as he can still draw a breath. None of my teammates will. Me? I've got a different problem. I feel like I live in a world made of cardboard, always taking constant care not to break something, to break ''someone''. Never allowing myself to lose control even for a moment, or someone could ''die''. But you can take it, can't you, big man? What we have here is a rare opportunity for me to cut loose and show you just how powerful I really am.