[It all started with Shredder's lair on a rainy night. Inside, there is Karai looking from the lair window. The girl looked at the torn paper of her deceased mother, Tang Shen, while thinking about what Leo had said to her in a flashback.]
Leo: Karai, don't do this. Splinter, he's your father. Your true father. Hamato Yoshi.
[End of flashback. Shredder walks towards Karai.]
Shredder: What is it that troubles you, Karai?
Karai: I want to know the truth. The truth about my mother. And Splinter.
Shredder: You know the truth, my daughter. Hamato Yoshi took your mother away.
[Someone opened the lair’s doors.]
Tiger Claw: I have returned.
[Tiger Claw arrives, now wearing an eyepatch on his left eye and a torn ear. Karai is shocked, while Shredder is surprisingly unfazed.]
Shredder: [Unfazed.] Tiger Claw.
Karai: [Shocked.] How? You were eaten by a giant alien worm.
Tiger Claw: [Walking towards Shredder and Karai.] And you believed such a thing could contain my hate? My hate is what kept me going. [Flashback begins.] As I tore my way out of the belly of the Kraathatrogon. As I battled through the armies of the Kraang across alien worlds that would drive lesser men mad. [Flashback ends.] And finally, back here, back to my enemies. [Kneeling toward Shredder.] I would have my revenge against Splinter, against his hideous reptiles, and against those who trapped me in that wretched worm's belly.
Shredder: [Calmly.] I will grant you this wish.
Karai: [Outraged.] What? It's because of him that Splinter and the Turtles are still alive in the first place.
Shredder: [Strictly.] Karai, you will go with Tiger Claw. Destroy Splinter and the Turtles at any cost.
[Tiger Claw and Karai start a hunt on the turtles.]
[Theme song.]
[In Murakami's restaurant, the turtles start their training.]
Mikey: [Looking furious.] I've put up with you guys for a long time, but this is about to get real!
Raph: You don't want this kind of pain, Mikey.
Donnie: Big talk for someone with such a limited vocabulary, Raph.
[Raph shoves Donnie away by putting his hand on his brother's face.]
Leo: Are you sure you're ready?
Raph: Are you kidding me? I was born ready.
Leo: Okay, Mr. Murakami.
Murakami: One pizza Gyoza, coming up.
[Raphael, Donatello and Michelangelo have bug eyes, get their tongues out and are drooling over seeing pizza Gyoza. Mr. Murakami throws the Gyoza to the turtles, as they're starting to fight each other for these as they pin each other to the ground. During their struggle, a pizza Gyoza falls on top of Mikey. Michelangelo closes his eyes and opens his mouth, believing that he will win the pizza Gyoza, but to his shock, a sword appears and it catches pizza Gyoza. It is revealed that Leo catches the Gyoza.]
Leo: Ha, I thought I'd play after all.
[Leo eats the pizza Gyoza and gives his brothers mocking smile. His brothers get up and get angry.]
Raph: [Looking annoyed.] What happened to Mr. "I'm too broody for this game"?
Leo: Mmm, these things are really good.
Murakami: My restaurant was never that popular until invented these for you.
[Mr. Murakami hands them a full plate of Pizza Gyoza. Turtles have heart shaped eyes, cut to the turtles’ hands taking away pizza Gyoza. The turtles eat their pizza Gyoza. While eating, Donatello notices Leonardo is glancing at the window, depressed about Karai.]
Donnie: He's still brooding.
Raph: He's thinking about her. About Karai.
Leo: Master Splinter is her father. How could she still want to be with the Shredder?
Mikey: [muffled] You have to have faith, Leo. Her entire life was shown to be a lie. This is a challenge to everything she knows. The truth will set her free. Just give her the time she needs to accept who she is.
Donnie: Right. Look, Leo, she'll come around.
Raph: [Distrustfully.] Yeah, well, personally, I hope she doesn't. I don't trust her, not for one second.
[While saying this, Raph doesn’t notice that Mikey mischievously took away his Pizza Gyoza.]
Donnie: You're right, Raph. You shouldn't trust anyone.
[Raph attempts to eat his gyoza, but finds out that Mikey took it and ate it. Furious, Raph tackles and beats him up. Meanwhile, up on the rooftops...]
Tiger Claw: Having a hard time keeping up, girl?
Karai: I was taking it easy on you since you're working with only one eye and no tail.
Tiger Claw: You think you're clever? You're a fool.
Karai: I'm the fool? You've faced the Turtles in battle before and lost. What exactly is your grand plan for revenge here?
Tiger Claw: To destroy warriors such as these, you don't strike at their limbs, you go for their heart.
Karai: And what does an overgrown cat know of the heart?
Tiger Claw: Why do you think the Shredder sent you with me?
Karai: [She thinks about it for a moment before her eyes widen in realization and horror.] Because I know them. I know the places they go. I know their weakness. Their friends April O'Neil and Casey Jones.
Tiger Claw: The riders of the worm. They will all pay for what they did to me.
[Back at Murakami-san's Noodle Shop, Murakami is cleaning the ship.]
Murakami: Hello? Is somebody there? Leonardo?
Karai: Not quite.
[Karai pins Murakami.]
Karai: The Turtles.
Murakami: I don't know what you're talking about.
Karai: Lying will only make this worse. Leonardo, Raphael, Michelangelo, and Donatello. Where do they live?
Murakami: I don't know. Please, please.
[Karai lets him go.]
Karai: There is no honor in this,
Tiger Claw: I didn't come here for honor.
[He bares his claws. Meanwhile, The turtles open the manhole cover to go home.]
Mikey: Guys, stop!
Leo: What is it, Mikey?
Mikey: I feel like we're forgetting something. Something important. Something something the fate of the world could depend on. It's right on the tip of my tongue.
Donnie: The Kraang?
Mikey: No.
Leo: The Foot clan?
Mikey: No.
Raph: The Rat King?
Mikey: No. Wait! I remember. My doggy bag. The leftover Gyoza are back at Mr. Murakami's. We have to go back. Fate of the world!
[As they return to the shop, they see that the shop is a ransacked mess.]
Donnie: What happened?
[Mikey sees Murakami on the ground, looking rattled and traumatized. Mikey comes to Murakami and comforts the innocent old man.]
Mikey: Mr. Murakami! Mr. Murakami, it's me, Mikey. Are you okay?
[Donnie and Mikey help Murakami to get up to his feet.]
Murakami: They came looking for you. They wanted to know where you lived. But I didn't know. They asked about your friends. To my shame, I told them everything I knew.
Raph: Who did this?
Murakami: The girl and the growling man.
[Leo sees the claw marks at the wall, which can only mean one thing…]
Leo: Tiger Claw is back. And he's going after April and Casey.
Donnie: We have to get to April... and Casey, you know, time permitting.
Raph: The girl has got to be Karai, Leo. I told you-
Leo: Not now, Raph.
Donnie: April's not answering her T-Phone. She always answers.
Leo: We'll split up. Me and Donnie will go to April's place, you and Mikey get to the ice rink and warn Casey.
Donnie: Why wouldn't she answer her phone?
[Meanwhile, Casey, April and Irma had watched a movie.]
April: Best movie ever! The part where the Captain is cornered by the monster, and it's all slobber and fangs and goo, and then boom, that explosion knocked them out of orbit and and they're falling into the star and and and--
Casey: [Annoyed.] I just don't get why our date had a third wheel attached to it.
Irma: Hello? I'm right here.
Casey: That's the problem.
April: Who said anything about this being a- [hears something]
Casey: What is it?
April: We're being followed.
Irma: What?
Casey: All right, whatever it is, we split up and lead it away from the third wheel here. Plan?
April: Plan.
[They walk off, leaving Irma alone, once more.]
Irma: Guys, am I missing something? [in defeat] Well, that's just great.
[Casey runs, heads to his apartment, grabs his bag and hides while he sees the coast is clear.]
Casey: Yes! Coast is clear. Casey Jones can't be caught. Aww, nuts.
[Tiger Claw lunged at him, but Casey electrocutes Tiger Claw with his taser]
Casey: Come on, tiger dude. Let's see what you.... got? You know what? On second thought, I don't need to see what you've got.
[The turtles have arrived at Kirby's home, while he tried to call April, but she did not answer.]
Kirby: She's not answering. She always answers.
Donnie: That's what I said!
Leo: Kirby, you said she went to the movies. That's where we start.
[April kept on running until Karai stops in front of her.]
Karai: O'Neil.
[April took out her tessen.]
April: You want to do this, Karai? Fine. But I'm warning you, I've been training with Master Splinter big time, and I'm ready to kick your butt.
Karai: I didn't come to fight. I came to talk.
April: Oh, well I've been trained in that, too.
[Casey is being tossed around while he avoid the kunai.]
Casey: Whoa! You know, part of me always wanted to fight a man eating tiger. Know any real ones?
Tiger Claw: Do you think this is a game?
Casey: Whoa! Yeah, keep away from one-eyed freaks. Or we could play a game of crush the cat. Later. Yeah! Woo! [climbs onto the cars while Tiger Claw follows] If it wasn't for the fact that I'm gonna die, this would be so cool.
[April listened to Karai talked]
Karai: All my life, I was raised to believe that the Shredder was my father, that Splinter was the enemy. So when Leo told me that Splinter was my true father, I couldn't accept it. But then I began to have doubts about Shredder's honor.
April: Doubts about the evil leader of the evil ninja clan? Really?
Karai: Yes, even now, the Shredder has sent Tiger Claw to destroy the Turtles. He's trying to use me to set a trap for them. But I can't. Even if it means betraying Shredder.
[Casey bursts onto the rooftop and throws a grenade.]
Casey: Taste exploding puck! Okay, cat man dude, you wanna do this? Let's do this.
[He dodges. Tiger Claw throws Casey away. Casey grabs onto the ceiling boards and attempts to swing himself to kick Tiger Claw, but the villain furiously grabs him and lifts him up.]
Tiger Claw: You will pay for what you did to me, the suffering you caused, the pain I endured.
Casey: You're not still mad about the whole worm thing, are you?
[Enraged, Tiger Claw ruthlessly throws Casey from the restaurant. Casey falls, screaming, then when he hit the ground, he groaned in pain as he realized he was critically injured. He weakly reaches forward to call for his friend. At the hockey rink, Raph is seen closing his eyes wearily, while Mikey slides through the ice. Raph's phone began to ring. Seeing this, Raph grabs his T-phone and answers.]
Raph: Casey? Casey? Casey, answer me! Something's wrong, Mikey. What are we gonna do?
Mikey: I know exactly what to do. We can use our phones to triangulate the position of Casey's T-phone by bouncing the locator signal off the satellite.
Raph: That's actually a good idea. It's like we're in some kind of alternate universe or something.
Mikey: You can also track pizza delivery guys that way. Booyakasha.
[Meanwhile, Leo and Donnie see April and Karai talking.]
Donnie: There's April. Come on! Get away from her.
April: Leo, Donnie, wait. You have to listen to what she has to say.
Karai: I believe you, Leonardo. I believe that Splinter is my true father.
April: I believe that she believes you.
Donnie: I believe April.
Leo: This… [amazed] This is great. I knew you'd come around. We'll take you to the lair to see Master Splinter.
Donnie: Whew. Raph's not gonna believe this.
[In the lair, Raph is outraged. Mikey is also trying to take care of Casey, who is bruised with a lot of wounds.]
Raph: [Furious.] I don't believe this! What have you guys done?!
April: Casey!
[April runs to Casey. Raph looks furious.]
Raph: [Angrily.] What world do you live in that it's okay to bring the princess of the Foot clan to out secret lair?
Leo: [Concerned.] What happened to Casey?
Raph: [Angrily.] Tiger Claw threw him off a building. And you just brought his partner in crime home for dinner.
Karai: Shredder lied to me! I didn't know.
Raph: [Threateningly takes out his sai.] Did you know that I'm about to stick this sai right up your-
[Leo pushes Raph away.]
Leo: Raph, no! She understands now.
Donnie: She gets it. She knows the truth, Raph. Everything's gonna be fine.
[Behind her back, Karai began to tap onto her communicator to alert Tiger Claw.]
Leo: Will you just listen?
Raph: I've heard enough from you and your girlfriend. She's probably leading the Shredder here right now.
Splinter: Enough!
[They stop and Splinter sees Karai]
Splinter: Miwa.
Karai: Splinter.
Splinter: Come with me.
[Karai follows Splinter into the dojo. Raph then punched Leo for bringing Karai here. In the dojo, Karai enters and was fascinated by seeing the tree. She approaches Splinter.]
Splinter: I retain very little from my old life, but this I will never let go my daughter.
[He gives Karai the photo and her eyes grew wide with shock. She looks at the family photo. She finally realizes that Splinter was her real father, not Shredder.]
Karai: I...I can't believe it. You're telling the truth. All these years, the Shredder has been lying to me.
[The turtles enter]
Leo: Wait, you can't believe it? I thought you did believe it. If you didn't believe it, why did you come down here?
Karai: [realizing] Father.... What have I done?
[Tiger Claw is in the alley, sniffing them out.]
Tiger Claw: Reptiles. Where are you? Underground, in the sewers.
Splinter: You had to see with your own eyes. You had to learn the truth for yourself.
Karai: You knew. You knew I was lying.
Splinter: No doubt the Shredder's forces are on their way.
Donnie: What was that last part?
Karai: Tiger Claw is tracking me.
[The turtles are so stunned with wide eyes about this but Raph is instead very furious.]
Raph: [Furiously.] I told you!!!
Leo: Karai!
Karai: There's no time to argue. I have to get out of here. I can- I can lead Tiger Claw away.
Splinter: Go. Take Karai and watch over her. I will stay with April and attend to Casey. You are who you choose to be, not what others make you.
Raph: Some of us choose to be right all the time.
Leo: Will you just go?
[They leave the lair. April is standing over Casey.]
April: Do you think he's gonna be okay?
Casey: [weakly, being delusional] April Why did you have to bring Irma again? She's so nasty.
[Splinter and April exchange weird looks on their faces, seeing that Casey’s okay, albeit still disoriented. In the Sewers, Karai and the turtles begin to lead Tiger Claw away from the lair and enter the main power source.]
Raph: Well, princess? You got us into this. Where to?
Karai: I... I don't know.
Mikey: Everyone, stop! I know exactly where to go.
Donnie: I feel scared.
[Tiger Claw entered a frozen meat room. He sniffed the air.]
Tiger Claw: I can't smell you, but I can hear you. Show yourselves! They're stalking me.
[Something knocked him, making him slice down whoever is near.]
Tiger Claw: Are you afraid to face me? [gets knocked down] Are you afraid to fight me?
[Sensing this, he grabbed Raph and threw him aside. The turtles are seen having white eyes.]
Tiger Claw: Let us finish this.
[The turtles appear and the lights go black, making them disappear. The turtles attack Tiger Claw, but he easily beats them. Mikey grabbed a hold of his arm while Raph tried to attack. Tiger Claw pulled himself free and easily started to beat them down at once. Leo crashes to the ground when Karai arrives.]
Tiger Claw: Karai, would you like the honor of finishing him?
Karai: I have no honor. But that's about to change.
[She attacks Tiger Claw but he disarms her. She kicks until Tiger Claw knocks her, almost near the saw. She gets up and fights but she was easily defeated. He grabs her just as Leo gets up.]
Tiger Claw: If you value her life, do not take another step. Just as I thought.
[He begins to leave with Karai]
Leo: No! Come on, we have to-
[Mikey is hurt.]
Donnie: Wow. I think his shell was knocked loose. We have to get him back to Master Splinter.
Leo: [Worried.] Karai.
Raph: I still don't trust her.
Leo: Are you kidding? She saved us.
Raph: The Shredder raised her. Daddy's probably welcoming her home right now.
[Back in the Shredder's lair...]
Tiger Claw: She has betrayed you, Master Shredder. She fought alongside the Turtles.
[Shredder lowers his head in shame.]
Karai: Tell me the truth! Splinter is my father, isn't he?
[Shredder closed his eyes, knowing that there is no point in lying to her about her true heritage. Shredder turns around and approached her.]
Shredder: [Bluntly.] Yes. Hamato Yoshi is your true father.
Karai: [Vivid.] What?
[Karai looks down, incredibly dumbstruck and flabbergasted about being lied to by Shredder. She realizes that she really is the daughter of Hamato Yoshi as Shredder walks over to Tiger Claw.]
Shredder: Tiger Claw, take her away.
[As a punishment for betrayal, Karai is thrown out in the cage at the dungeon.]
Karai: No. No! No! What are you doing? NOOO!
[Karai cries out in despair as the episode ends.]
[Note: Leo's voice actor, Jason Biggs appeared as a latest and Leo's new voice actor is going to be Dominic Catrambone for the rest of the season (but the voice of D.C is also similar to J.B)]