When Ultimate Drako scatters the Turtles and Master Splinter, Donatello ends up in a bad future where The Shredder rules the world and his brothers are no longer a team. Determined not to give up, Donnie reunites his brothers for one final fight with the Shredder...

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!! This episode provides examples of:
* AdmiringTheAbomination: Stockman can't help but compliment himself for the Shredder's newest exo-suit he created for him, which he believes is unbeatable.
* AlternateUniverse: And a bad one, that ''Turtles Forever'' will later confirm as one of the many universes in the franchise's multiverse.
* AndThisIsFor: Donatello shouts "For Master Splinter!" when beginning the attack.
* AnArmAndALeg: Somewhere along the way, Future Michelangelo lost his left arm.
* AnyoneCanDie: By the time Donnie arrives in the future, both Splinter and Casey have perished. Hun and Stockman are killed by Ch'rell. Mikey is cut down by the Karai legions, while Karai kills both Leo and Raph. April then kills Karai, and finally, Ch'rell is killed by Donnie.
* ApologeticAttacker: Karai is genuinely remorseful about slaying Leo, asking for his forgiveness as he succumbs to his wounds.
* ATeamFiring: A heroic example occurs in this episode: Don sprays the Shredder's giant exosuit with the two Gatling guns on his own exosuit's shoulders, and not one of the bullets hits Ch'rell, who is completely exposed in this particular exosuit.
* BadFuture: What can happen if TheBadGuyWins. The Shredder rules with an iron fist, with his massive army having wiped out all but April's resistance cell. The population lives a bleak existence, all as the Shredder prepares to expand his scope to the rest of the galaxy.
* BadassLongcoat: Future Leo sports one.
* BatmanGambit: Donatello never intended to beat the Shredder head on, due to what Stockman told him about the exo-skeleton. Instead, he planned to just get him close enough to the Turtle Tunneler's drill and use it to rip him apart. He knew full well that the Shredder would provide the opportunity by stopping to gloat and declare victory.
* BerserkButton: Splinter's death is a sore spot for Future Raphael, as he believes they could've saved him had Leo not insisted on a retreat. The suggestion that he's responsible for their father's death enrages Future Leo, to the point where he's ready to settle their differences once and for all before Donatello intervenes.
* BewareTheNiceOnes: Donatello is at his peak here, killing the Shredder without a second thought as retribution for what was done to his family and the overall planet.
* BigBrotherIsWatching: TheTeaser ends with Karai reminding the enslaved population of this, as a warning to always behave.
* BigNo:
** Raphael shouts this after Karai kills Leonardo from behind.
** Donnie after being shown Splinter's grave.
** Donnie again when Future!Mikey gets killed in front of him by Karai's forces, leading to his UnstoppableRage below.
* BittersweetEnding: This episode ends with the future Utrom Shredder killed, but Donatello has to witness his brothers die first and in the end, April is [[SoleSurvivor the only main character still alive]]. Thankfully, Don’s return to the present ensures that this future never happens.
* BloodlessCarnage: In the BadFuture, we see Leo, Raph, Mikey, Karai, and Shredder himself all killed off in the FinalBattle. Not a drop of blood is shown, but even so it doesn't take away from the DarkerAndEdgier feel of the episode.
* BondBreaker: Future Mikey says the team fell apart, after Donatello's sudden disappearance. Donnie's tech skills and more relaxed personality balanced out the others' hotheaded quirks, and they couldn't function as a unit without him.
-->'''Future Mikey''': When you never came back Donny...well, everything just...fell apart. We were a team. Without you, it just didn't work. Guess we really needed that level head of yours.
* CallBack: Donnie talks to April about [[Recap/TeenageMutantNinjaTurtles2003S3E17TimeTravails the Turtles' recent trip to 1406]]. She doesn't doubt it for a second, citing their interdimensional experience with [[Recap/TeenageMutantNinjaTurtles2003S2E21AprilsArtifact Augie's artifact]].
* ChekhovsGun: While surveying the ruins of the lair, Donatello observes the Turtle Tunneler is still intact. He later puts it to good use when infiltrating the Shredder's base and taking him down for good.
%%* ContinuityCameo: This episode is full of references to the Archie and Image TMNT comics.
* CrapsackWorld: The Earth under Shredder's rule. Much of New York appears to be in ruins, and survivors are forced to work 18 hour shifts in Shredder's factories.
* DarkerAndEdgier: ''Boy howdy!'' By the end of the episode, every main character not named Donatello or April O'Neil is killed off.
* DeadAlternateCounterpart: Future Mikey takes Donatello to Splinter's grave, saying he performed a HeroicSacrifice. We later learn that Casey has also died.
* DeathSeeker: Hun is so broken by finally having been discarded by his master, and having lived several years in a grotesque amalgamation with Stockman, that he openly wishes he was dead.
* DueToTheDead:
** Splinter is buried in the park. Mikey explains that the place meant a lot to him because Hamato Yoshi used to take him there back in the day.
** April keeps a photo of Casey hanging on the wall of her group's hideout. It's later said he died during a failed attempt to storm the Shredder's headquarters.
* TheDyingWalk: When Karai cuts down Leo from behind and then defeats Raph, the wounded Raph drags himself over to Leo so he can die at his brother's side.
%%* EvilOverlord: Shredder is one for the entire planet Earth as well as the Utrom homeworld.
* EyeScream: In the alternate bad future, Raphael is missing his left eye and Leonardo is presumably blind without the use of both of his eyes as he has to wear dark shades all the time.
* FamilyUnfriendlyDeath: All of the Turtles of that dimension are brutally killed by Karai and the Karai-bots, Baxter Stockman and Hun are stomped on by Shredder's giant exosuit, and the Shredder gets a drill thrown into his Utrom face and getting obliterated, are all shown on-screen.
* FatalFlaw: Donatello reminds Shredder of his tendency to declare victory before actually assuring it. He then demonstrates the true point of this attack.
%%* FinalBattle: Both the Shredder and Karai are killed in this episode. It's an alternate future, however.
* {{Foreshadowing}}:
** This episode’s placement close to the end of the season is meant to foreshadow not just the Shredder’s endgame in the main timeline, but also to bleakly show what will happen if the Turtles fail to stop him in the season finale.
** At the beginning when Donnie is chatting with April he starts to talk about how he looked into her Uncle Augie's research before getting cut off by Ultimate Drako, Augie's fate would later be revealed in "The Trouble with Augie".
** This episode shows just how far deep Karai's loyalty to Shredder really is, even if the one here is an alternate doppleganger, that she ultimately helps her father TakeOverTheWorld and murders that Universe's Leonardo and Raphael. If this Karai went that far for Shredder, what does that says to the other one?
** Ultimately averted with Hun, who is shown conjoined with Stockman. Season 5's cut episode "Nightmares Recycled" would've revealed that he was born with the Garbageman as his conjoined twin, which this arrangement with Stockman was seemingly meant to foreshadow until the episode was cut.
* FutureBadass: Leonardo, Raphael, April, and especially Mikey. And though we don't see her onscreen, Angel is apparently one of the rebel leaders.
* GalacticConqueror: Shredder has taken over the Earth and the Utrom Homeworld and rules the planet with an iron fist. He's now working on a transmat device so he can spread his dominion to the stars, enslaving one world after another.
%%* GoneToTheFuture: Apparently occurs to Don in this episode.
* GreatOffscreenWar: How Shredder managed to gain control of Earth. TheTeaser shows he has a massive army of robots, which has systematically wiped out various resistance movements.
* HeelFaceTurn: Hun and Stockman defected to the resistance after they saved them from being executed at Shredder's hand, though Hun is so broken by his pitiful state of existence that he begs for the Shredder to take him back. Stockman is more invested in the conflict at hand given he's always hated the Shredder and has plenty of good reason to want to help overthrow him.
* HeroicSacrifice: Mikey says that Splinter gave his life to save his remaining sons a few years after Donnie's disappearance.
* TheHeroDies: In the future timeline, Leo, Raph, and Mikey all perish fighting the Shredder and Karai. It's not known what happened to this timeline's Donnie, but by the end of the episode, all four Turtles are gone from the timeline.
* HopeBringer: Shredder has conquered Earth and the Utrom homeworld and the turtles have given up any hope of defeating him until Donatello returns.
* HopeCrusher: Shredder announces to the world that his forces have wiped out the last major resistance group and that he's planning on expanding his scope to the rest of the galaxy, all to make the general population feel that it is useless to try to oppose him. With the Shredder's vast resources, even Future Leo and Raph thinks the situation is hopeless.
* IOweYouMyLife: Hun and Stockman joined the resistance in return for being saved from execution, though Hun mostly stays with them due to not having any better option.
* IWorkAlone: Implied. None of the remaining three Turtles work together anymore, but they also don't appear to be part of April's group. Future Mikey simply says he knows people that can help rather than refer to himself as a member of the team, and his brothers have to be contacted through special channels.
* {{Irony}}: With [[TheSmartGuy Donatello]] completely incapable of explaining his predicament, Future Mikey makes light of him being at a loss for answers for once.
%%* ItsAWonderfulPlot: Don discovers just how horrible the world can be when he's been gone for over 30 years.
%%* KilledMidSentence: Mikey.
%%-->'''Future Mikey''': Donnie! Donnie! I'm--
* LastOfHisKind: Only briefly. Donnie is the only survivor of the Turtles, but as he returns to his timeline, this leaves this timeline with the Teenage Mutant Ninja Turtles extinct.
* LogicalExtreme: Both Hun and Karai show they have gone to this.
** Hun finally failed the Shredder one too many times and was completely devastated when the Shredder finally did try to execute him for it. He's spent most of Season 3 in a slump due to repeated failures, and only got his way back into decent standing in "Hun on the Run". Seeing him as a shriveled, weak man forcibly conjoined with Stockman, begging for his old job back, is just a way to show where he was headed if he hadn't succeeded in the aforementioned episode.
** Karai's UndyingLoyalty to her father does nothing but enable his conquest of the Earth and the Utrom homeworld, and soon the entire universe. She also finally proves willing to murder the Turtles for her father, albeit with some reluctance.
* LosingTheTeamSpirit: Mikey tells Don that when he disappeared '30 years ago' their team just fell apart.
* MoralityPet: Don is this to the older versions of his brothers in this alternate timeline. They are battle hardened warriors who don't get along with each other. The second Don shows back up in their lives and wants to fight against Shredder, they bury the hatchet as best they can for him.
%%* MyGodWhatHaveIDone: Karai, when she killed Leo. Though she didn't have enough time to angst over it as April shot her with a missile.
* NoodleIncident:
** Splinter's HeroicSacrifice. He stayed behind to ensure his remaining sons could escape, but Raph broke ties with Leo for refusing to go back and try to save him.
** The remaining Turtles did try to breach Shredder's headquarters and take him down, but his army was too vast and powerful. Future Leo says this is how Casey died.
* OhCrap: Hun's only reaction to the Shredder being about to kill him is a muted, "Oh, crud."
* OOCIsSeriousBusiness:
** Donatello is typically the most laidback and rational of his brothers, with this episode in particular noting he's a calming influence. Future Mikey being cut down in battle causes him to lose it, to the point of vowing to kill the Shredder. He makes good on it in the end.
** Future Mikey is first seen taking down a squadron of law enforcement officers literally [[StealthPun single-handedly]], before angrily confronting a bewildered Donnie for "abandoning" them and revealing that none of the remaining brothers are on speaking terms. This is a far cry from the happy, fun-loving Mikey of the present-day, and the years have clearly taken their toll on him.
* OutOfCharacterMoment: Don absolutely slaughters Ch'rell at the end, a far cry from his usually pacifistic actions. Understandable, of course given the circumstances.
* PartyScattering: The Turtles and Master Splinter are scattered throughout time and space by Ultimate Drako.
* PragmaticVillainy: Shredder kept Stockman around for most of the 30 years since Donnie's disappearance before finally growing sick of him. Even after he enslaved the Utroms, Stockman's brains were apparently just ''that'' valuable.
* PuttingTheBandBackTogether: Donny reunites the Turtles for one final fight with the Shredder.
* TheReasonYouSuckSpeech: Shredder is less than impressed with Donatello's opening attack.
-->'''Shredder:''' 30 years and ''this'' is all you have? Truly pathetic! ''[rips the arms off Don's exosuit]'' Disgusting creature!
* RewardedAsATraitorDeserves: When Hun begs the Shredder to be on his side again, The Shredder simply stomps on him.
* ShoutOut: The opening is a shout out to George Orwell's novel ''Literature/NineteenEightyFour''.
%%* SlasherSmile: Ch'rell has only grown more depraved after decades of unopposed rule so he sports this often, but particular mention goes to the one he makes after killing Hun and Stockman.
* SoleSurvivor: Discounting the time displaced Donatello, by the end of this episode Future April is the only main character still alive.
* StealthPun: The Shredder is destroyed by the Turtle Tunneler, that is to say, ''shredded''.
%%* TheStoic: Mikey. Considering all of these tragic events that happened during Donnie's TimeSkip, the change is jarring.
* ThereIsNoKillLikeOverkill: April kills Karai by firing on her with a bazooka.
* TheyReallyDoLoveEachOther: Despite decades of estrangement and lingering hard feelings between them, Raph is devastated when Karai kills Leo, rushes at Karai himself in a rage, and when she fatally wounds him in turn, he crawls over to Leo's body to die beside him.
* ThisCannotBe: Donatello's reaction to seeing the state of the world and when told he's been gone for over 30 years.
* ThisIsUnforgivable:
** After stating a BigNo upon watching the Karai Legions kill Future Mike to his horror, Don gets pushed too far. His response? "You'll pay for this, Shredder! If it's the last thing I do, YOU WILL PAY!"
** Also occurs when Future Leo is cut down by Future Karai while his back was turned. An enraged future Raph clearly tries to kill her for it.
* UndyingLoyalty: Hun is so inexplicably loyal to the Shredder that even being used as a human test subjected and marked for execution doesn't stop him from pleading to be welcomed back into the fold. Shredder responds by stomping him to death.
* WeMeetAgain: When the reunited Turtles break into his headquarters, Shredder notes it's been 30 years since he saw all four of them together, and he relishes the chance to finally finish them.
* WhamLine: When Donatello is about to be arrested, someone suddenly comes to his aid. It takes a few moments for him to get a good look and realize who it is.
-->'''Donatello:''' Mikey?
* WhatHappenedToTheMouse:
** It's not known what exactly happened to this timeline's Donatello, only that he disappeared 30 years ago.
** The only main Earth-bound characters who appear from this timeline are the Turtles, April, Hun, Stockman, the Shredder, and Karai, with Casey and Splinter already being dead. While the conquered Utroms appear, Angel is the only other ally of the Turtles to be seen or mentioned. Other notable allies like Leatherhead, Honeycutt, or even the other prominent villain of the season, Bishop, go unmentioned, but one could safely presume they all fell in battle.
* WhoDares: Shredder's reaction to the Turtle Tunneler suddenly bursting into his headquarters. The reunited Turtles are only too happy to answer.
* YouHaveFailedMe: We learn that just a few years prior to Donnie's arrival, Ch'rell finally had enough of Hun and Stockman and prepared to execute them. They were rescued by April and Mikey and defected to them, partially due to having no other choice. Their stay of execution comes to an end when Hun goes to beg for his old job back, and Ch'rell kills them both.
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