While Mikey, Don, and Splinter fix their new home, Leo and Raph are picking up stuff from their old home. The latter expresses vengeance on the one who sent the killer robots. As they arrive, they started watching the news about Dr. Baxter Stockman, head of Stocktronics, creating a Mouser robot, the same kind of robot that attacked the Turtles.
Meanwhile, Dr. Stockman's assistant, April O'Neil, finds herself in trouble when she attempts to find out what her employer intends to really do with the Mousers.First appearance of April O'Neil and Baxter Stockman
This episode provides examples of:
- Be Careful What You Wish For: Raphael says this to Leonardo when he wishes to see him try to fight him.
- Bystander Syndrome: Splinter's opinion on Stockman.
Raphael: Why can't we just go topside and show him a little mean and green?
Splinter: Because I forbid it!
- Chronic Hero Syndrome: This is how Leonardo is convinced by Raphael to go out of the lair to follow the Mouser.
- Evil Mentor: Stockman is this to April right before she tries to find out what his plans are for the Mousers.
- Honor Before Reason: Leonardo briefly tries to stop Raphael from going against Splinter's orders of leaving the lair. As soon as the Mouser that Donatello rebuild escapes, he follows Raphael's way of leaving the lair as well.
- Let's You and Him Fight: The first time◊ Leo and Raph fight against each other. Though it's just briefly before they noticed the Mouser than Don rebuild to follow them to Stockman has convinced the two into working together.
- She Knows Too Much: Now that April knows of his plot, Stockman sends his Mousers after her.
- I Heard That: As soon as Splinter left the room, Michelangelo does the pose and imitation of his quote.
Mikey: "We will resume your training in the morning."
Splinter: I heard that.
- I'm Taking Her Home with Me!: Mikey, about April at the end of the episode:
"Can I keep her?"
- In the Back: Stockman grabs April with a giant claw and drop her to the Mousers. Ironically, he has a remote control behind his back to control it.
- Right Behind Me: April attempts on finding out what Stockman is planning to do with the Mousers.
April: Rat problem, my eye. What are you really up to, Stockman?
Stockman: Now now, Ms. O'Neil. That would be telling.
- Screw the Rules, I'm Doing What's Right: Against Splinter's orders, Raph tried to sneak out to stop Stockman, only for Leo to arrive and stop him. After seeing Don and Mikey following the Mouser to its source, Raph asks if he's gonna let it get away so Leo has no choice but to pursue it as well.
Raph: So you're just gonna let that Mouser roam free?
Leo: Master Splinter is so gonna kill us. Well, are you coming or what?
Raph: If you insist...
- Second Episode Introduction: For April and Stockman.
- Skilled, but Naive:
April: But aren't you already a very rich and powerful man?
Stockman: Ah, Ms. O'Neil, so brilliant yet so naive.
- Shout-Out/ Hurricane of Puns: Mikey and Don saying the name of their new place.
- Sound-Only Death: The Turtles are shocked to see a Mouser chewing on the mouse off-screen.
- Tempting Fate: When Raph threatens Leo of fighting him to get pass through him:
Raph: Look, I'll go through you if I have to.
Leo: I'd like to see you try, hothead!
- What the Hell, Hero?: Leo and Raph call each other out for trying to leave the lair and trying to stop him from dealing with Stockman, respectively.
- Earlier on, Splinter calls out Raph for his attempt of leaving the lair to deal with Stockman.
- Before long, Raph asks Leo if he's allowing the Mouser to get away as soon as it leaves the lair. This finally convinced him to leave the lair as well to follow the Mouser.
- Why Don't You Marry It?: Raph's opinion on Donnie saying how the Mousers they fought against are becoming more powerful.
- You Can Run, but You Can't Hide:
Stockman: You can run, Ms. O'Neil, but you cannot hide from my Mousers.
- You Watch Too Much X: While Michelangelo is complaining of wall-crawling based on one of the characters, Leonardo says this.
Leonardo: You read way too many comic books.