A 309-es kísérlet megérkezik a Földre, és tüskéivel elveszi az itt lakó emberek és űrlények eszét, így Stitch-ét is. Ez nem jön a legjobbkor, mert Lilonak másnap szüksége lenne rá az Ohanarán, vagyis egy tudásvetélkedőn. Pleakley és Jumba besegít neki, de úgy tűnik Mertle ellen nincs sok esélyük. Amíg ki nem derül, hogy Mertle csalással vezet, amikor is Lilo hasznát veszi a 309-esnek, vagyis Tüskének.

Jumbo elutazik, Pleakley pedig kikíséri. Nani ekkor jön rá, hogy az űrlény csupa egészségtelen étellel tömi Lilot. Nani utasításba adja, hogy innentől kezdve csak egészséges és tápláló ételeket készíthet. Ennek Lilo persze nem örül, így éppen jókor jön a 062-es kísérlet, akinek fő feladata az ellenállhatatlan táplálékkészítés. Viszont a jóból is megárt a sok. Lilo és Stitch hamarosan gurulni kezdenek.

Lilo megismerkedik Victoriával, akivel rögtön megtalálják a hangot. A kislány reménykedik, hogy talált egy új barátot, ám Mertle rögtön lejáratja. Lilo, hogy bebizonyítsa, ő nem fura, bulit rendez. Szerencsétlenségére a 355-ös kísérlet pont aktivizálódik, ami nagy baj, hiszen ő két egyén között személyiség-átvitelt hajt végre. Így a bulira mindenki mindenkivel személyiséget cserél. Ilyen körülmények között kellene bebizonyítani Victoriának és Mertle-nek, hogy Lilo és a családja normális.

Pleakley és Jumba szállodát szeretnének nyitni, a többi űrlény és Lilo is segít nekik. Igen ám, de időközben aktivizálódik a 113-as kísérlet, akinek a fő funkciója a negatív esemény keltése. Vagyis, aki kapcsolatba kerül vele peches lesz. Így nehéz lesz vendéget szerezni.

Lilo és az osztálytársak pénzgyűjtést rendeznek a sziget javára. Csokit árulnak, aki a legtöbbet eladja, az fagyibérletet kap. Szerencséjükre találkoznak 020-as kísérlettel, akit Jumba annak idején arra hozott létre, hogy eladja ördögi találmányait. Vagyis a fő funkciója, hogy mindent eladjon. Így fordulhat elő, hogy mire észbe kapnak, 020-as pénzzé tette a családi házat és az ingóságokat is.

Experiment 089: SKIP

Lilo's desire to hurry and grow up is immediately satisfied when Skip, experiment 089, arrives and ages her up to a 17-year-old and then a 27-year-old. Lilo soon realizes she wants to be age 7 again because she misses out and ruins the future. She must figure out how to "reset" herself.

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 505: PLOOT

When Lilo sets out to clean the pollutants from the Grotto where Pudge the fish lives, she comes across Ploot, a.k.a Experiment 505, eating all the litter around him.

Experiment 277: SNOOTY

After making zombie calenders, Lilo, Stitch, and Victoria encounter experiment 277, a vampire bat like experiment who was made to find and enrich Snootonium, a dangerous chemical that is similar to mucus. Can Lilo and Stitch safely catch Snooty bafore Victoria, who is distrustful and teams up with Gantu to slay him?

Experiment 210: RETRO

Nani meets some of her friends from high school and tries to impress them by saying she is vice president and they convince her to introduce them to her family. The day only gets worse when experiment 210, tries to revert everyone back to a prehistoric state...

Experiment 248: BELLE

While out trying to prove the existence of the Night Marchers (an ancient Hawaiian legend), Lilo, Mertle, Stitch, Jumba, and Pleakley tell each other scary stories. Meanwhile an experiment 248, later known as Belle, is being chased by Gantu.

Exxperiment 316: MORPHOLOMEW

(Crossover with American Dragon: Jake Long)

Lilo enters the island's skateboarding competition in an attempt to win the heart of her one and only crush, Keoni. At the same time, Jake, Gramps and Fu Dog visit the island to check out reports that magical creatures - actually Jumba's experiments -- are running rampant.

Spats

(Crossover with The Proud Family)

The Prouds pack their bags for a Hawaiian vacation on. Lilo prepares for the grand re-opening of Jumba & Pleakley's Bed Not Breakfast and eagerly awaits the arrival of their scheduled guests - Mr. Cooper, a reviewer for Relaxing Times Magazine, and the Proud Family who are attending Wizard Kelly's Smack-up Throw-down Hi-wyan Style Y'all. While trying to impress Mr. Cooper, arguments ensue when Suga Mama accidentally activates Experiment 397, "Spats" causing friction among all. It's up to Penny and Lilo to find the cure.

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 128: BUGBY

Lilo, Stitch, Jumba, and Pleakley are turned into bugs after Lilo captures an experiment for her bug collection.

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.

When Dr. Drakken and Hämsterviel team up to kidnap Stitch in order to mass multiply him in order to destroy the world, Kim Possible and Lilo set off to try and save Experiment 626. Jumba, on the other hand, is quite sure that a certain Naked Mole Rat is his experiment 607...

Experiment 285: LAX

(Crossover with RECESS)

The gang from Recess are on 'holiday' in Hawaii! But experiment 285 is on the loose, causing Vince, Mikey and Stitch to abandon any and all forms of work. Can Lilo stop 285 and Hamsterviel's new experiment locator satellite without Stitch, or will Gantu finally succeed in catching an experiment?

Note: This episode first aired on Disney Channel on September 5, 2006 at 5 a.m.

Experiment #276: Remmy | On the anniversary of the day when Lilo's ohana became broken, Lilo desides to take a nap, the day only gets worse when a nightmare causing experiment enters her dreams.

Lilo & Stitch learn that Mrs. Hasagawa has adopted a lot of cats that are not cats at all but experiments.

Experiment #262: Ace | When Jumba is in danger of losing his membership to E.G.O. (Evil Genius Organization) he has to show the leader that his experiments are still evil. But when Experiment 262 is activated and according to the experiment computer it has no evil function, things get worse.

Experiment 223: Glitch | Jumba automates the house, but an experiment gets into the computer and the house goes crazy! Can Lilo and Stitch save the day?

Nosy, (who escaped at from Gantu's ship at the end of Woops,) complains to Lilo about the fact that she just left all the experiments behind and never found their one true place. (Lilo and Stitch never went back and saved them). So, Lilo plans to save them, especially Angel. But when Snafu, a plan ruiner is on the loose, will Lilo be able to save Stitch's cousins?

Experiment 251: LINK

After being inadvertently activated, Experiment 251(later called Link),starts joining people together with a sticky rope. He joins, among others, Lilo and Mertle, Jumba and Pleakley, and Nani and Stitch. Will Lilo be able to capture the experiment? Will teamwork save the day?

Note: This episode is the bonus episode on the Leroy and Stitch DVD.