It's finally spring break, and the Possible family (with Ron and Rufus in tow) travel to Florida to help Kim's paternal grandmother ("Nana" Possible) get settled into her new retirement community (called "Chez Leisure"). While Kim and her Nana love each other very much, Kim finds her grandmother to be very overprotective, being critical of her missions and essentially treating her like a little kid. Meanwhile, Ron plans to take advantage of Spring Break, since no one there knows him, but his plans to pick up girls [[EpicFail ends as badly as pretty much everything else he does]]. Unknown to them both, Dr. Drakken and Shego are also in Florida, as Drakken's planning to broadcast a {{mind control}} signal into the MP3 players of the college kids on spring break, turning them into an army he can then use to {{take over the world}}.

While investigating a strange signal picked up by Wade, Kim locates Drakken and Shego in an ice cream truck and gives chase, but they manage to escape, thanks to an inadvertent distraction from Nana. Returning to his current lair (an abandoned alligator farm somewhere in the Florida swamps), Drakken activates his signal, but instead of the college students MP3 players, it affects the hearing aids of the seniors; still, Drakken decides to use them anyway and has them commit several robberies. While waiting for an analysis of a strange substance found at one of the robberies, Kim recognizes it as part of her Nana's lemon squares and follows her and the other seniors to Drakken's lair, where she is captured.

Ron meanwhile, tries to take advantage of Rufus's popularity with the college students, when Wade contacts him about Kim; wondering what to do, he comes up with the idea to advertise a party at Drakken's lair. Meanwhile, Kim escapes being fed to Drakken's crocodiles, so he forces her to fight her Nana, who she learns lived an adventurous life, not unlike herself. During the fight, Kim manages to turn off Drakken's signal, freeing the seniors, just as the spring break-college students show up, trashing the lair and destroying the satellite that would've spread his signal all over the world, although [[VillainExitStageLeft Drakken and Shego manage to escape]].

Back at the retirement center, Nana Possible has finally let go of her critical, overprotective attitude towards her granddaughter, and she and Kim enjoy some bonding time over martial arts before Kim and Ron are called away on a mission to fight some giant spiders in Guam.
!!This episode provides examples of:
* ContinuityNod: The fact that Wade has [[Recap/KimPossibleS1E9AttackOfTheKillerBebes Ron microchipped]] is referenced again.
* CurseCutShort: Played with in a ShoutOut to ''Film/{{Shaft}}'':
--> '''Drakken:''' Your Nana is a bad grandmother--\\
'''Kim:''' Shut your mouth!\\
'''Drakken:''' I'm just talking about Nana.
* FreezeFrameBonus: The inside of Drakken's teen slang dictionary can be read if you pause at just the right moment.
* HomemadeSweaterFromHell: One of Nana's friends made one, and Nana puts it on Kim to [[BareYourMidriff cover her up properly]].
-->'''Kim:''' ''(with a forced grin)'' Thank you. Wool is so comfy...when it's 98 degrees.
* IKnowMaddenKombat: After the mind control signal is cut off, several of the victims join the fight. One of them takes Shego down by sliding a shuffleboard puck under her foot, which causes her to trip.
* MassHypnosis: Drakken's plan--it works, just not on the targets he initially had in mind.
* NeverHurtAnInnocent: Drakken sends Nana Possible to attack Kim, taking advantage of the fact that Kim can't bring herself to actually hurt her own grandmother. This ends up leading to...
** NeverMessWithGranny: Nana Possible's a trained martial artist ''and'' the first woman to complete the Navy's underwater demolition training. She's still able to put up a good fight at her current age, which is initially a big problem for Kim...but ends being an even bigger problem for Drakken once the mind control is broken.
* NotInTheFace: Drakken says this trope verbatim when Kim and Nana Possible are about to attack him, so they punch him in the chest instead.
* SoProudOfYou: Kim and Nana Possible say this to each other at the end of the episode.
* SpecificallySuspiciousDenial:
--> '''Ron:''' ''(to Wade)'' How'd you find me? Do you have me microchipped or something?
--> '''Wade:''' Uh, that's not really important right now.
* VillainExitStageLeft: Drakken and Shego manage to escape in their ice cream truck at the end of the episode.
* WhatAreRecords: Averted--Nana Possible gives her two grandsons some vinyl records, and Jim and Tim know what they are, but they decode to convert them into MP3-files.
* WildTeenParty: When Drakken tries to launch his mind control satellite, some of the spring-break crowd arrives, push him and Shego aside by sheer numbers, and turn the place into a dance party (converting his equipment into a sound system).
* WritingAroundTrademarks: The game the Possible family plays, "Strategories" seems to be a combo of several board games; its title is a combo of ''Stratego'' & ''Scattergories'' but it also has a race car piece like ''Monopoly'' and categories a'la ''Trivial Pursuit.''