This episode begins with the turtles continuing to search for more mutagen containers. Raphael tells Donatello to relax, and that April will come back eventually. Donnie agrees and keeps searching. Donnie gets a reading from his gadget that a mutagen canister is up on a tall roof. They climb the building and eventually find it. Donnie says that they only have sixty-three containers left. Without the turtles noticing, Karai is on another rooftop, spying on them. She starts to think that it's going to be more fun all over again to try and defeat them.
While continuing to find more containers, Michelangelo yawns in boredom, saying that the search is getting too boring and screams sarcastically very loud, which causes Leonardo to tell him to stop and they will play a fun game: training. He explains near a Chinese-looking building, saying it is like King-Of-The-Rock. Leo goes across the wire to defend his territory and without knowing, Raphael has a plan. Sooner or later, Leonardo goes across in between the wire again to fight his brothers. Mikey puts on his headphones and starts to dance on the wire. Leo says it is not fighting, but Mikey ignores and starts to make him tilt and causes Mikey to jump across the wires. Leo says it wasn't fair, but Donnie steps ahead. Donnie uses his mathematical skills to determine where he should strike his brother with his shuriken. Leo gets exhausted for blocking so many and realizes that Donnie also made it to the other side with Mikey. Leo asks Raph what "trick" he'll get from him. Raph asks sarcastically, "What are you talking about?", but throws his weapons at Leo and kicks him out of the wires, causing Leo to fall down, along with his two blades; reading, "Lame-o-nardo". Leo starts to get mad and objects that they are always not taking his training seriously. Raph argues that they should train their way and he'll train it his own way. They walk away from him and leaves Leonardo looking upset at his sword.
Leo talks to Master Splinter about how his brothers treat him disrespectfully, and he wonders if he has the skill to be the leader. Splinter comments that how can his brothers appreciate him if he has a lack of self-confidence. Splinter then walks away, and the scene then switches to Karai in Bradford's dojo, looking at a picture of her now deceased mother. Then, a squad of robotic foot ninja approach her from behind and challenge her. She holds her ground for a while, but is then grabbed by the arm and pinned to the ground. The Shredder interferes and orders the ninjas to stop attacking her. Shredder the tells Karai that he is going to Japan to attend to urgent business, and that should Karai make any move on the turtles whilst he is gone, the consequence will be fierce.
This episode provides examples of:
- Adaptational Badass: The Foot Ninja robots are much more aggressive, have an Adaptive Ability that allows them to learn from their opponents, and are generally a much bigger threat than the Foot Ninjas these ones seem based on. Not even Conservation of Ninjutsu seems to slow them down.
- An Aesop: Leo learns to not be so rigid with his command and fighting moves, while the other Turtles learn to not brazenly disregard his orders.
- Awesomeness by Analysis: The Foot Bots can learn and adapt to an opponent's fighting style by watching them.
- Not to mention Donatello using this to perform his Pinball Projectile attack.
- Big Brother Instinct: After their fight, Leo tells Karai that her grudge is with him alone and warns her to never try to threaten his family again.
- Bound and Gagged /Distressed Dude: Happens to Leo when Karai captures him.
- Call-Back: There's plenty of it. Raph calling Leo "Lame-o-nardo", the Bradford Dojo, Karai bringing up Leo double-crossing her in Enemy of My Enemy, Raph using pigeons to block security cameras, and Karai being Splinter's daughter.
- Combat Pragmatist: Raph pulled this off and later so did Leo against Karai.
- Continuity Nod: The turtles are still trying to get the mutagen, and April is still mad at them.
- Curb-Stomp Battle: Leo does this to Karai when he becomes a Combat Pragmatist.
- Dance Battler: Mikey gets past Leo by dance fighting to throw him off his guard.
- Dropping the Bombshell: Splinter finishes the episode with only 4 words.Splinter: Karai is my daughter.
- Foreshadowing: During Leo and Karai's fight, there's a billboard that says "Stockman Industries" with a picture of a Mouser.
- Kick the Dog: When Karai asks Shredder if he'd let the Foot Bots finish her off, he ignores her completely.
- Mecha-Mooks: The Foot Ninja Robots of course.
- My God, What Have I Done?: When Leo is captured, the other Turtles (Raph in particular) blame themselves for not adhering to his order to retreat.
- Mythology Gag: There are tons of mythology gags this episode; from lampshading the absurdity of the '87 series' trenchcoat disguise to having Mikey briefly chant part of Vanilla Ice's Ninja Rap.
- Pet the Dog: Karai still holds a grudge toward Leo, but she hasn't entirely forsaken her honor over it. Before she sics her Foot Bots on the captive Leo, Karai returns his swords to him to give him a fighting chance.
- The Unreveal: We don't see Leonardo's reaction to finding out Karai is technically his sister. A little disappointing, given all the Dating Catwoman between them.
