A small-time thief goes on a crime spree when he stumbles upon a form of artificial intelligence made of nanotechnology that escaped from its containment. When the crook and his ward reach April's new antique shop, "2nd Time Around", they face off against Casey and the Turtles.

On another note, April and Casey meet for the first time in this episode when the turtles bring him along to help out at April's shop, but their relationship is off to kind of a rocky start.

''First appearance of Nanobot''
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!!This episode provides examples of:

* AbusiveParents: The scientist that created the nanobots finds their childlike personality annoying and electrocutes them when they try to come together.
* BecomingTheMask: At first, Harry takes advantage of Nano's need for a daddy to have a tool to commit crimes with. But at the end of the episode, it's clear he's developed some affection for Nano.
* BittersweetEnding: Poor Nano.
* CradlingYourKill: An interesting case occurs when Harry [[spoiler: picks up Nano's mask after he accidentally causes Nano's "death". Since the mask is all that is left of Nano it counts, since Harry holds it in his arms and talks to it as though it is Nano]].
* CrazyPrepared: Leo's first plan was to simply attack Nano rapidly before he could rebuild. When that fails, Leonardo and Donatello opt for Plan B: luring Nano into a trash compactor. When that proves to be a bust, too, Raphael really hopes there's a Plan C at the ready. Leo does, immediately telling Donnie to get in position (shown to be the junkyard's electromagnet).
* DistractedByTheSexy: Happens to April when she meets [[{{Hunk}} Casey]] for the first time. She is turned off by [[ManChild his]] [[InnocentlyInsensitive personality]], however.
* FriendshipMoment: April is worried about the recent robberies in the neighborhood and asks the Turtles to spend the night. The Turtles are happy to do so.
* {{Jerkass}}: Harry, the nanobot's "daddy".
** JerkWithAHeartOfGold: Although by the episode's end, he seems to see his "son" as more than just a meal ticket.
* HopeSpot: The Turtles manage to force Nano into the compactor and crush him down. Raph and Mikey in particular are certain it's over, only to see Nano reforming.
* ManChild: Nanobot has the mind of a little kid, possibly a toddler.
* MeetCute: April and Casey's first conversation is very awkward.
** BelligerentSexualTension: ...but their relationship escalates to this at the end of the episode.
* MistakenForAliens: Harry mistakenly thinks the turtles are invaders from Mars...
** MythologyGag: ...just like Casey did in the 1980's cartoon.
* MuggingTheMonster: Casey stops Harry from getting away after robbing April's shop. Too bad for him that Harry was backed up by a very protective robot.
* MyGodWhatHaveIDone: Harry is reduced to tears and frantically apologizing, in response to accidentally killing Nano.
* NanoMachines: Guess who?
* RaisedHandOfSurvival: How the Turtles see Nano survived the trash compactor.
* ShoutOut:
** The Turtles first try and take out Nano in a [[Film/TheTerminator trash compactor]], then dump him in [[Film/Terminator2JudgmentDay molten lava]].
** Nano grabs the Battle Shell, stopping it dead no matter how fast Mikey tries to accelerate.
--->'''Donnie:''' Faster, Mikey! It's taking us apart!\\
'''Mikey:''' ''[in a Scottish accent]'' [[Series/StarTrekTheOriginalSeries I'm givin' her all she's got, Captain! She cannot take no more!]]
* SympathyForTheDevil: In the end, Mikey admits to feeling sorry for Nano, saying he was technically just a kid.
* TemptingFate:
** Lampshaded by Mikey, as Nano reforms after a would be BondOneLiner at the trash compactor. He notes how his puns just keep asking for trouble.
** Returning to the shop, Leonardo remarks he's glad the fighting is finally over. The Turtles walk in on April and Casey yelling at each other.
* ThisIsGonnaSuck: At the junkyard, Donatello uses his scanner to try to find Nano.
-->'''Michelangelo:''' I know it's been used before, guys, but I'm gettin' a baaaaaad feelin' about this.\\
''[Nano emerges and makes himself even bigger than before]''\\
'''Michelangelo:''' And now I'm gettin' an even badder feeling about this.
* TragicVillain: Nano simply wants a family and unknowingly took to a criminal as a father figure. In trying to help and protect Harry, Nano runs afoul of the Turtles and reacts with anguished wails when injured by their weapons. His death is portrayed as a tragedy rather than a victory, with even Mikey feeling bad for him.
** Even Harry qualifies. It's implied that he was BornUnlucky. At first, he sees Nano as a tool to make himself rich, but he starts to grow attached to him and breaks down in tears when he destroys him.
* WakingNonSequitur: When Leo wakes the others up to investigate a noise, Mikey mumbles "Can I have another s'more?" They weren't eating s'mores, so this came out of no where.
* WoundedGazelleGambit: Casey did take some nasty hits when facing Nano, but Raphael can tell he's playing it up as worse than it is so that he can be alone with April.
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