While the Technodrome floats through the sky and begins to wreak some havoc (and terrify thousands upon thousands of citizens, including bandits) throughout the city, Splinter and The Shredder are in the latter's inner-sanctum, with Splinter reminding him of the two's past. He voices how he once had practically everything he could want in an eternity a true family and the many bonds of love on his side. However, the Shredder's envy is what made himself give up all of his own, peaceful assets and it is also the one thing that lead him to become a truculent individual that chose to leave Splinter with nothing. A couple flashbacks are then shown, during which Shredder is seen walking and walking further away from a traumatized Splinter, who is hampered by part of the house set ablaze. In the present, Splinter vows to end this incredibly pointless feud once and for all. At first, Splinter seems to have all of the circumstances completely within his reach, but the Shredder then uses all too familiar deceptive tactics. When Splinter stands up on one of the posts, he then looses his balance and falls; Shredder vanishes in this moment. Shredder then tries to waste some of Splinter's ammunition by acting as if he is in a certain area (which he is not). The orange lights then activate once again and, naturally, Splinter is forced to make just a brief run for it, but Shredder then stops him.
Meanwhile, the Turtles are just realizing that the Technodrome has weapons and they are forced to struggle to avoid the laser blasts while still on their gliders. In a short matter of time, they are all separated from one another (due to all of the blasts) and land on different rooftops. However, they quickly regroup and decide that they have to speak with Splinter in order to find out what their very next move should be.
When they reach the lair, however, they only find Kirby, who is still brainwashed (unbeknownst to them), and he tries to attack Mikey with a bo the first instance that he sees him. The other three then tackle Kirby and immediately spot the mind-control device on the back of his neck. Once Kirby has fully revived, he regretfully explains what has unfolded Shredder has joined a temporary alliance with the Kraang, Splinter has presumably gone to face the Shredder, and April has been captured and has already been taken into the Technodrome.
On board the massive Kraang warship, April is bound to an obscure, metal "table" and quickly awakens to see the gigantic form of Kraang Prime staring right down at her. It quickly explains to her that her arcane mental energies are 'uniquely attuned' to the whole universe and, once Kraang Prime has gained what she possesses, it will somehow use it to utterly transform the Earth into a world for The Kraang. April then retorts that the billions of human beings are "kind of" using the world, so, in short, Kraang Prime basically came all this way for not a thing. But then a swarm of electrodes then appear and converge on April and all suddenly goes black.
The Shredder and Splinter continue on with their harsh duel, both quite equally matched. Shredder then falsely tells Splinter that the latter took Tang Shen utterly away from him; though Splinter counters that she never, ever was to be his. Splinter then grabs hold of a rope that he brought along inside his pocket and he does manage to wrap it around The Shredder's forearm and then his entire body, though the latter manages to break free and the rope quickly falls apart. Splinter then comments that the one and only thing that Saki ever had was his objectionable hatred (and his overt obsession) for almost everything, and if he does end up overwhelming and defeating Splinter, he will have not a single thing to live for. However, the Shredder then says that he is dead wrong and he then claims that he actually was able to take something away from Hamato as an apparent form of "retaliation" of his daughter, Miwa.
In yet another flashback, it is revealed that Oroku stole her the very night that Tang Shen was killed after the events of their very first battle, raised her as his own child, and named her 'Karai'. As expected, Splinter becomes very upset due to yet another sudden tribulation in his life and this in itself ends up leaving him quite vulnerable, as the Shredder is able to turn the tide of battle in his own favor for a moment with some forceful punches. The Shredder then stands right over a downed Splinter with triumph and mocks him, saying that, when he is long gone, his own daughter will go on through the remainder of her days cursing his name. Implied by the look in Splinter's eyes after this statement, Splinter seems to have been pushed far over the edge, much like he was when both Shredder insulted him when he was with Tang Shen years before, and when The Kraang droids had cornered him in an alley way in New York, right before he was mutated into the rat that he is now. The Shredder goes in for a fatal strike, but miraculously, Splinter ends up dodging and catching the gauntlet in his teeth, and uses all of his inner-force to partially break it's alloy. He then flips over and kicks backwards to strike the Shredder squarely in the chest, right before lunging right towards him, teeth first.
Meanwhile, the Turtles are able to smuggle themselves aboard one of the capture pods that The Kraang are using to abduct people and animals, and are soon brought inside the massive Technodrome. Upon exiting the pod, they quickly both find and figure that The Kraang have been generating anti-gravity (anti-gravitons) within the ship...They then hear April screaming somewhere, but, before they can determine her location, they are set upon by dozens and dozens of floating Kraang. Meanwhile, within Kraang Prime's chamber, April has now been fitted with a terrifying helmet-like device that is quickly siphoning up her cerebral energies and transferring them into Kraang Prime. The Kraang leader then successfully begins to use these energies to begin the planet-wide mutation of Earth, but the Turtles burst in, having totally battled their way there (by following the sounds of April's two screams). Raph then kicks the giant alien brain very hard between the eyes and retreats, while Donnie frees April as quickly as possible, shutting down the active mutation ray in the process. The unsuspecting heroes then make a move to escape, but Kraang Prime then pulls itself out from the wall and pursues all of them within it's gigantic robotic body.
Meanwhile, at the Foot Headquarters, Splinter is finally beginning to defeat The Shredder with a complex array of moves that combine traditional Ninjutsu with his own agile, rat-like movements. A final strike ends up sending the Shredder flying all the way across the room, which knocks the helmet from his head, revealing the horrible scars and burns upon the villain's face. Splinter then picks up a katana that was dropped and leaps into the air to end his mortal enemies' life once and for all, but is stopped in his tracks by Karai, who has now entered the equation. While Splinter is stunned to be in the presence of his long lost daughter, Karai manages to graze Splinter's shoulder with a swing of her sword and then runs to the aid of her false father, who quickly informs her that the rat is none other than Hamato Yoshi. Splinter then adresses Karai as 'Miwa' twice (in an apparent attempt to calm her just a little), which utterly confuses her. Nevertheless, this also ends up changing her former mindset completely and she then becomes quite a bit more malevolent, self-serving and argumentative than ever before in the series, as she now truly has a recollection of - and deeply cares about - one of the many lies that the Shredder had easily made her believe long ago (that Splinter had put an end to her dear mother's life). When Karai is about to attack her true father yet again, Shredder then chuckles evilly when he sees that Splinter is emotionally shattered. Heartbroken, Splinter decides to leave the building, and Karai yells coward as he does so.
The Turtles race to escape the ship, with Kraang Prime approaching close behind them. Mikey is soon cornered and he begins to fall down one of the countless narrow apertures on the inside base of the ship. An energy cannon on Kraang Prime then begins shooting lasers at Mikey also, but Leo manages to slice the energy cannon right off of Kraang Prime's body and is eventually able to rush his young brother to safety. Leo now stands alone against the monster, as his brothers have rushed to the very last escape pod. Leo boldly Mikey's kusarigama chain all the way around Kraang Prime, and then urges his brothers to flee much to their own resentment. The escape pod then jettisons out into the nearby Atlantic Ocean, followed by the Technodrome itself shortly thereafter (though the cause of it's crash is unknown), which sinks very far into the murky depths. April and the Turtles (particularly Raph) then mourn over the loss of their eldest brother, until it is revealed that he was able to escape at the last moment. The other pods with the abducted people then reach the surface as well, while the five gladly celebrate their victory and are able to find their way back to the city.
At the lair, the Turtles engage in a continuation of their celebration, but Splinter is awfully quiet while Splinter is looking carefully and intently at the picture of his family, April goes up to him and apologizes for her words earlier that day. He tells her that there is no need, for she spoke truly from her heart. Leo then notices that something is on his sensei's mind and asks about what it could be. Splinter replies that he learned some things from the Shredder, but the revelation of those things is for another time. Our heroes then triumphantly celebrate their victory with quite a big dance party.
The episode ends at the very bottom of the ocean, where the Technodrome now lays. However, it slowly begins to light up, indicating that it might indeed make its return soon enough.
Splinter meets Karai for the first time, only to find out that Karai is none other than his missing long-lost daughter, Miwa.
The scene where the Technodrome is underwater is similar to events in the 1987's series; in that incarnation, the bottom of the sea is one of the numerous places that it has been stranded....
This episode marks the very first appearance of Kraang Prime, in spite of the fact that he has always been commanding the Kraang throughout this entire season.
Apparently, Kraang Prime is the only Kraang with the ability to speak relatively sensible English without the use of a robot body.
During the dance party at the end of the episode, various dance moves are used:
When Donnie and April are dancing in unison, they are doing the chicken dance.
When Raph is dancing alone he does a to b-boy moves then ends it with a freeze.
"Mikey: I think i speak for all of us when i say... aaaaa...!!
Raph: What the heck is that thing?
Leo: It's the end of the world.
Donnie: Actually,it's just the end of
humanity's reign As the planet's dominant life form. You know, like the dinosaurs...
Leo: Now? Really? You're going to do this now?
Donnie: Well, excuse me, but it's how i deal with stress!
Raph: Well, maybe it doesn't have weapons. Does it looks like it has weapon?
Leo: I think it has weapon."
"Splinter: Oroku Saki. You were once my friend. I thought of you as my brothers. 15 years ago, i was a different man. I had everything i could want. A loving wife and a beautiful daughter. Let's name her Miwa. And you, my loyal friend?. Jealousy consumed you. You sought that which was mine. You took everything that i loved. And still you hunt me down.Everything!. So i fight you now. To end this.
Leo: Donnie! Mikey!
Raph: What now?
Donnie: Are you guys all right?
Leo: We need to talk to Splinter. Come on."
"Leo: Hello? Sensei?
Raph: Spike. Don't scare me like that, buddy.
Mikey: Anyone in here?
Mikey: Whoa, dude, chill! Agh!
Raph: What the heck is going on?
Donnie: Guys, check this out.
Leo: So what is it?
Donnie: I think it's a mind control device.
Mikey: No, stop it, stop it!
Donnie: Mr. O'neil? Are you okay?
Kirby: I've done something terrible.
Donnie: Well, it wasn't your fault, Mr O'Neil. Just tell us what happened.
Kirby: It appears the Kraang have formed an alliance with your enemy, Shredder.
Kirby: That's not all. i fear the Shredder has handed April over to the kraang.
Donnie: Shredder kidnapped April?
Raph: Sensei must have gone after her.
Donnie: So where is april now?
Kirby: They're taking her to the technodrome
Raph: The what?
Carlos Chang: Carlos Chang O'Brein Gambe here. Pandemonium in the streets as a "tecno-terror-dome" hovers over downtown
Mikey: Dude, this is getting freakier by the minute.
Raph: We just escaped that freaky sphere and now we gotta break into it?
Kirby: Hmmm. In a matter of hours. The world we once knew will be gone. The kraang want April to help in their conquest of Earth."
"Kraang Prime: April O'Neil. Kraang has waited a long time.
April: Where am i? What's going on?
Kraang Prime: Like all kraang, i am called Kraang.
Kraang Prime: But you can call me Kraang. Kraang has need of this planet for kraang to live on.
April: Um, that's great, but we're kind of using it. So you came all this way for nothing. Bummer.
Kraang Prime: No. Kraang came all this way for you, April O'Neil.
April: Oh, really? As if i have anything to offer to you kraangs.
Kraang Prime: Your mental energy is uniquely attuned to this universe. Once kraang gains this abilty, kraang will transform your world into a world of kraang.
April: And how are you going to do that, exactly?"
"Splinter: Why you must persist in this insanity?
Shredder: You took Tang Shen from me.
Splinter: She was never yours."
"Carlos Chang: Run for you ever-lovin' lives because they're abducting us!
Carlos Chang: That's right men, women, children. Even pets aren't safe.
Kraang: Kraang must collect human specimens for kraang.
Leo: We gotta get in one of those pods.
Donnie: But how? There are eight kraang droids. Between us and there.
Leo: We could create a diversion.
Raph: Excuse me, how many did you say there were?
Mikey: We could all dress up like robots, sneak in.
Donnie: Or i could try to override their security codes by.
Leo: Or.. That... Might work. Let's go."
"Splinter: You never had anything but your hatred. And if you defeat me, you will have nothing!
Shredder: Hahaha... That is where you are wrong. You took something for me so i took something from you. Your daughter.
Splinter: No. It can't be."
"Leo: Okay, guys, this is it. On Three. One, two , three.
Raph: What the heck is going on?
Mikey: I think the kraang forgot to pay their gravity bill. ah!
Donnie: It appears the kraang have generated anti--gravitons.
Leo: Is there any way for you to generate anti-anti-gravitons?
Donnie: You mean gravitons?
Mikey: Guys, i'm gonna throw up. Or down. Or maybe sideways. But one thing's for sure. I'm majory gonna throw.
Leo: We still have a job to do, so let's go.
Mikey: Yo, zero-g is banging. The kraang should turn this into a carnival ride.
Leo: Uh, i think they're more interested in using it to destory the earth.
Mikey: It could do both.
Donnie: It's April!
Raph: Can you say that a little louder? I don't think the entire technodrome heard you. Never mind. They did.
Kraang Prime: Yes. Yes! It's Working!
Leo: That can't be good.
Shredder: It's over, Hamato. Soon, you will be no more. And your own daughter will go through her life cursing your name."
"Leo,Raph,Donnie,Mickey: Wohoo.. Yeah!
Kraang Prime: April O'neil, your mind belongs to kraang. Soon, your world will be ours. Let the planetary mutation. Begin.
Kraang Prime: Witness the end of your kind.
Leo: Not if we can help it.
Kraang Prime: The Turtles? Kraang will not stopped by pathetic mutants.
Mikey: At least we're not stupid aliens.
Leo: Raph, quick.
Kraang Prime: Ow!
April: You're my hero.
Raph: Hey, chuckles. We gotta get out of here.
Donnie: Let's go."
Splinter: Miwa? Ugh.
Shredder: Karai. That rat is Hamato Yoshi.
Karai: My name is Karai. Father told me what you did to my mother. And now i'm going to return the favor.
Karai: Why won't you fight? Coward!"
"Mikey: Leo, I have a question.
Leo: Can it wait?
Mikey: Not really. Did we beat that big kraang thingie?
Leo: Yes, Mikey, we did.
Mikey: Okay. Then why is it following us?
Donnie: Everybody, there's one last escape pod up ahead.
Mikey: Ow... Ah...
Leo: Get away from my brother!
Leo: Hurry, Mikey.
Kraang Prime: There's nowhere for you to run, mutants.
Donnie: Leo, Leo!
Kraang Prime: All of you will die here!
Splinter: With the world at stake, the only thing of importance is that you complete your mission no matter what you have to sacrifice. Or who.
Kraang Prime: No!
Leo: No. Get out of here now!
Raph: What are you talking about?
Mikey: Dude, you can't do this.
Leo: Go! I Can't Hold it back
Donnie: We gotta go now!
Donnie: I can't believe it. We made it.
Mikey: Leo... No!
Mikey: I Can't Believe he's gone.
Raph: I gave him nothing but a hard time. If i had it to do over again, i'd definitely be nicer.
Raph: Leo? Leo! Leo, you dork! You scared the heck out of us.
Mikey: We won! Oh, man, i love you, bros."
"Mikey: Who saved the world?
Leo,Raph,Donnie: We saved the world!
Mikey: I'd "who saved the world?"
Leo,Raph,Donnie: We saved the world!
Mikey: I'd Said..
Raph: Stop asking!
Mikey: We saved the world. Oof.
April: Sensei, i want to apologize. For the way i spoke to you earlier.
Splinter: No need. You spoke what was in your heart. I am just relieved that you made it home safely.
Leo: What's wrong, Sensei?
Splinter: I learned some things from the Shredder
Leo: Like what?
Splinter: That's for another time, Leonardo. Tonight is for celebration. After all, it is not every day you make the world safe from an alien invasion.
Mikey: You got that right. Everybody, Who saved the world?
Leo, Raph, Donnie, Kirby: Mikey.
Leo, Raph, Donnie, Mikey: We saved the world!
When Leo is holding back Kraang Prime and tells his brothers to escape, Donnie is the one to grab Raph and pull him back into the escape pod. When the chain snaps and Kraang Prime misses catching the escape pod, the scene flips back to Raph, who breaks out of Mikey's hold, not Donnie's hold.