When Leonardo secretly allies himself with Karai, he gets himself into deeper danger than he could have realized.
- Bait-and-Switch: Splinter lectures Karai on the pain her crusade is bringing to her friends, and Karai agrees to end her campaign against Shredder's assets and struggling empire... Because she's going to go after Shredder personally next time.
- Big Damn Heroes: The Turtles arrive just in time to save Karai and her ninjas from Tiger Claw.Leo: I feel like I'm making a habit of saving you lately.Karai: Well, maybe if you could arrive five minutes earlier...
- The Bus Came Back:
- Hun makes his first appearance since "Meet Mondo Gecko", as do the Purple Dragons, which aired about year and a half ago in real time. The chemical factory featured in Hun's debut episode, "Casey Jones VS. the Underworld", also appears again.
- Bebop and Rocksteady have their first major appearance since "Annihilation: Earth", nearly a year prior.
- Continuity Nod:
- Leo, Karai, and Shinigami attack the chemical factory first visited in "Casey Jones VS. the Underworld."
- Splinter heals Donnie with the healing mantra he first displayed back in "The Deadly Venom."
- Disappointed in You[=]/So Proud of You: After Leo admits his actions to Splinter, Splinter says this word for word to Leo for being blinded by vengeance, but is impressed that Leo own up to his terrible mistake.Splinter: I have always warned you of vengeance. I am disappointed in you, Leonardo. But I am proud you had the courage to admit your wrongdoing.
- Everyone Has Standards: The fact that the Shredder used a Buddhist Temple for a money-laundering operation disgusts Shinigami especially.Shinigami: Your dad was one messed-up freak.
- Evil Costume Switch: More like "morally gray" rather than evil, but Leo wears some armor with a black mask for most of the episode.
- Gamer Chick: Shinigami is seen playing on a PSP in one scene.
- Game-Breaking Injury: Donnie is knocked unconscious by the explosion destroying the chemical factory leaving him out of the action.
- My God, What Have I Done?: Leo is so guilt-stricken that his activities and secrecy lead to Donnie getting seriously injured, that at one point he comments that he might not be fit to be their leader.
- Mythology Gag:
- Leo's quasi-Foot attire bears resemblance not only to the attire 2003 Leo wore in "Same As It Never Was", but also to past incarnations of Slash. Him being in the Foot with the black mask also is reminiscent of his time there in the IDW comics.
- Karai and Shinigami have recruited an army of human mercenaries to serve as their own Foot soldiers, which is the first time the Foot have had human cannon fodder since the first season.
- While it's a fairly generic traditional hat, the hat's that the new army of Chromedome's wear bear resemblance to those worn by the Foot Elite, who debuted in 2003. Tiger Claw even refers to them as his "Elite Foot Bots".
- Raph recalls a Noodle Incident where Leo talked him out of dressing as the Nightwatcher vigilante, referencing Raph's fan-favorite vigilante alter-ego persona in the 2007 CGI film.
- Not So Above It All:
- April plays Mazes and Mutants with the turtles.
- When the Purple Dragons are defeated, Shinigami gleefully throws their money around and asks what kind of cool stuff they should buy.
- When Karai and Shinigami are waiting for Leo in their lair, Karai is training while Shinigami is playing a hand held video game.
- No-Sell: The Elite Foot Bots take everything Karai's ninjas throw at them without even flinching.
- Protagonist-Centred Morality: Raph, Donnie, and Mikey following Leo is considered entirely justified, and Leo is blamed for Donnie getting hurt in the course of following him. Leo himself barely attempts to argue this, even though he never intended for his brothers to be in harm's way, because it's simply understood that none of them are supposed to act alone and that they had no choice but to find out what Leo was up to.
- Punch! Punch! Punch! Uh Oh...: Karai's Foot Ninjas against the Elite Foot Bots.
- Ship Tease: This time, Shinigami is more receptive to Mikey's flirting.
- Stock Scream: Poor Wilhelm gets kicked off the catwalk by an elite Foot Bot.
- Trash the Set: The chemical factory from last season is destroyed.
- True Companions: Leo is pretty Easily Forgiven by his family once he apologizes, with a major Aesop that he shouldn't keep secrets from his brothers and needs to be loyal to them first.
- What the Hell, Hero?: Everybody gives Leo hell for being a covert Foot operative and unintentionally getting Donnie injured.
- The Worf Effect: Hun and Bebop both are easily outclassed by Shinigami. Later, Karai and Shinigami don't fare quite as well against the Elite Foot 'bots at first.
- Your Mom: Played for Laughs when Mikey insults Rocksteady by saying his mother wore combat boots... Only for Rocksteady to reply that his mother really did wear combat boots.Mikey: (To Rocksteady) Your mother wears combat boots!Rocksteady: Hey! Mother does wear the combat boots!
