Lilo is upset when Mertle gets a nice-looking fancy hairdo. But when she encounters a hair-eating experiment, Clip, she decides to get her revenge on Mertle by placing it in her bedroom with the plan of ruining Mertle's hair. But the plan runs amock and the experiment eats Mertle's mom's hair instead, and now the experiment is loose on the island. Now Lilo and Stitch must track down the experiment before everyone goes bald!

Lilo and Stitch have captured a new experiment, #254. He is insanely cute too, and charms all of Lilo's friends. Stitch is jealous though, so at the first chance he gets, he lets Gantu capture him.

As luck would have it, 42 hours after the experiment's activation, Mr. Stenchy releases such a foul stench, the area he releases it in is uninhabitable for decades. But without knowing of when Mr. Stenchy was activated, how will Lilo and Stitch save him before he releases the smell?

It's Hallowe'en! Lilo has dressed up as a gory character, while Nani is trying to get everything ready for the trick-or-treaters. Sadly, the house never gets any trick-or-treaters, but Nani wants to fix this. However, Experiment #300, Spooky, is activated, and it can turn into anyone's greatest fear. So, it makes it's way to Kaiaulu Hale's Hallowe'en party, and is terrifying everyone. Can Lilo and Stitch stop it?

It's Mertle's birthday, and she's got a brand new bracelet! But Lilo soon finds out it's got an experiment pod, though she doesn't know the number. So, Stitch goes undercover for her, and discovers it is the pod for Experiment #606. Now Lilo must get the pod back as quickly as possible; as #606 is an experiment that can suck in the entire world!

A bird has discovered a strange blue ball in her nest. After deciding she doesn't need it, she discards it into the river running below her tree. It turns out it's #520's pod, and it activates. Now the experiment is wreaking havoc over the island with it's huge behind by bouncing and shaking the ground. So, Lilo and Stitch must capture it, but Gantu is on it's trail too.

Mertle has got a new dog; Gigi. Little does she know, it's really Experiment #007, a dog that can keep everyone in the neighbourhood awake with it's loud yapping. So, Lilo and Stitch must protect it from Gantu, but have to go to a dog show to do it.

It's Lilo's birthday, but no one has remembered. So, she decides to give herself her own party. However, during the day, Experiment #303 is activated and wipes Lilo's, Stitch's and Gantu's memory. Lilo and Gantu, who think they are Martha and Lenny go after Stitch, who has returned to his natural destructive programming, and so they think is a criminal.

A new show called 'Look at This!' is going to be broadcast lives in the Birds of Paradise Hotel, and everyone is excited, except Lilo and Stitch. At the same time, Experiment #383 is activated and is a hynotic experiment. Hamsterviel sends Gantu after it to hynotise everyone who watches the episode of 'Look at This!'.

Things soon break into chaos when Lilo and Stitch capture Swirly from Gantu and take him home, ending up hynotised, and Swirly is recaptured. Will Lilo and Stitch realise who they are? Will they recapture Swirly and give him his one true place?

The Hula Girls have ditched Mertle for Lilo, and consequently, Lilo neglects Stitch to hang with them at the Kauai Medieval Festival. So, when Experiment #586 is activated, Stitch needs someone to capture it with. And who does he team up with? Mertle. Strangely, Stitch and Mertle are having fun trying to capture the metal eater, but this ends when it storms the Medieval Festival.

Lilo finds the pod for Experiment #509, which is a plant experiment. Lilo wants to activate to find it's true place, but Jumba won't let her and locks it up. However, when she makes a bet with Mertle, she breaks the lock and activates #509 and dubs it Sprout. But things get out of control at the Kauai Town Fair, and Stitch has a showdown with a cowboy.

In a trip to the observatory, Lilo and Stitch overhear Cobra telling an astronomer about a huge asteroid heading towards Earth. Lilo and Stitch go around Kauai telling the people to evacuate with them onto their ship. Stitch also warns his cousins. However, only 6 Experiments - Digger, Swirly, Hammerhead, Sparky, Spooky and Kixx - and a surfer from the beach arrive at the ship. So, Stitch comes up with a new idea; Digger will drill a hole to the center of the asteroid, it can be smashed. Things seem to be going to plan, but they soon find out something lives on the asteroid, and their plan comes crashing down.

Experiment #604 - Houdini

Stitch and Pleakley are working up a terrible magic act to perform at one of Mertle's parties, so Lilo secretly helps them out by activating Experiment #303, Houdini, which can make things disappear and reappear with a blink of it's eyes. But when Gantu crashes the party, things go wrong, and Stitch is made invisible and Houdini gets away. And just to make things worse, Mertle's aunt, who is a big LA producer, wants to make Stitch a star because of his magic act, but only Lilo, Jumba, Pleakley and Houdini know it is phony.

Experiment #458 - Finder

Experiment #458 can find absolutely anything, so Lilo names him Finder. And when she takes him to show-and-tell, he's a huge hit, upstaging Mertle. Mertle is bitter, so she searches for something to compete with Lilo's show-and-tell. Unfortunately, she is unsuccessful. That is, until she sees Hamsterviel on planet Earth!

Experiment #297 - ShortStuff

Stitch is getting really upset about people thinking he's too short, so Pleakley uses Jumba's growing ray to make Stitch bigger. Meanwhile, an experiment is activated and it is soon short circuiting mechanical devices all over the island.

Experiment #608 - Slugger

After Pleakley's incompetence in baseball causes Lilo, Stitch, and Stitch's cousins to lose to Mertle's team, Lilo and Mertle arrange a rematch, with Lilo's collection of Elvis records and Mertle's collection of dolls on the line. Lilo finds Experiment #608, aka 'Slugger', and decides his projectile-deflection skills would make him an excellent pinch-hitter for her team. Unfortunately, Mertle gets her own ringer in Gantu, and makes the rematch a game of basketball instead of baseball, with Slugger on the line as well! Can Lilo and the experiments win under these circumstances, or will they need help from an unlikely source?

Experiment 319: SPIKE

Lilo and co. set out to beat Myrtle and her family in the Ohana-Rama.

Experiment 355: SWAPPER

When Swapper swaps Lilo and Stitch's brains, Lilo thinks it will be impossible to get Victoria, a new girl, to think that she's not weird.

Experiment 020: SLICK

Chaos ensues as Slick, a fast-talking experiment who can sell anything to anyone, teams up with Lilo and Stitch to sell candy bars for the Hale Kaiulu's annual fundraiser. Lilo soon learns the hard way that Slick is not designed to stop, and she and Stitch must reclaim their household items before it gets too late.

Experiment 029: CHECKERS

Lilo is angry and under appreciated about her float not getting chosen for the parade, and being grounded (along with Stitch) by Nani and Pleakley.

Experiment 133: PJ

Lilo's always getting blamed for Mertle's pranks, so she figures it's high-time to pull a few pranks of her own, and what better prank-ee than the mean old substitute hula teacher?

Experiment 322: HECKLER

Experiment 322 is activated just in time to taunt Pleakley as he makes his stand-up comedy debut at Nani's charity event. While Lilo is first amused by his off-the-cuff jabs, especially towards Mertle, she soon learns that mean words only hurt if you let them.

Experiment 267: WISHY-WASHY

Lilo learns a valuable lesson in being careful what you wish for when Experiment 267 is activated.

Experiment 540: PHOON

Lilo quits experiment hunting go to Hula Hip Hop Fusion school. Meanwhile, Experiment 540 is unleashed, causing Gantu to take a bad blow to the head. Jumba new device causes Phoon to mutate into a giant monster. And Gantu thinks thing like 625 and Hamsterveil are just figments of his imagination.

Experiment 234, designed to collect private enemy conversations through her tail, is accidentally activated by Lilo. When she gets into trouble after overhearing part of a conversion and thinking that Mertle hates her friends, Mertle, out of anger, willingly helps catch experiments for Hamsterviel.