When unable to go to a Renaissance festival with Lilo (who has taken Yuki, Teresa, and Elena with her), Stitch winds up teaming up with Mertle against an experiment that eats metal and grows bigger with each bite.
A man is selling a vintage car to a younger couple, but while hosing it off, some water gets on an experiment pod wedged in the car's grill, activating experiment 586. 586 eats the entire car and runs off, leaving a dumbfounded buyer and seller.note
On Gantu's ship, Reuben tricks Gantu into letting him draw a mustache and goatee on his face. Just as Gantu is about to pummel Reuben for this, the ship's computer warns of an activated experiment — one that eats metal and grows exponentially larger when it does. Gantu makes preparations to capture the experiment using his ship, as it is too big to contain with normal means.
Meanwhile, Mertle and her friends are listening to the radio, hoping to win free tickets to the local Elizabethan Renaissance fair. However, it turns out that Lilo was the lucky caller to win the tickets, and she invites all the girls to come with her. Mertle refuses on principle, unwilling to lower herself to hanging out with "Weirdlo," but to her absolute shock, the other three girls don't seem to have a problem with that as long as they get to go to the fair. Mertle is left in the dust with no friends and nothing to do.
586 continues his metal-eating rampage as he enters a sugar factory.note A tour group drives by in a bus, and the tour guide directs everyone's attention to 586, talking about how factories and urban sprawl are driving this "dwindling wildlife" extinct. However, it ends up being the other way around, as 586 drives the factory extinct by eating the entire building. 586 is now as large as the tour bus and trudges off in search of more metal to eat.
Lilo and her new friends are getting into princess costumes for the fair and exchanging Elizabethan insults. The girls, usually just Mertle's cronies, realize that they're having a lot more fun than they do at Mertle's house, since all she usually wants to do is play dolls. Meanwhile, Jumba is getting into costume as well — dressed as Henry VIII. Turns out, he can respect a man with a tendency to behead his wives.
Lilo, Stitch, the three girls, Jumba, and Pleakley all arrive at the Renaissance festival, announced by trumpets and a singing minstrel. There are no dogs allowed in the fair, so Stitch is not allowed in. Although disappointed, he knows how important it is to Lilo to have fun with her new friends, so he tells her not to worry about it. Stitch leaves and happens to run into Mertle, who points out that Lilo seems to have dumped him just like Mertle's friends dumped her. Before much else can be said, however, 586 bursts through some nearby trees toward town, prompting Stitch to run after him.
Meanwhile, everyone else is enjoying the Renaissance fair. Jumba is participating in a haggis-eating contest, Pleakley gets to be Queen for the day, and Lilo and the girls are enjoying getting their hair braided. Stitch comes back to the fair to warn them of the massive experiment rampaging on the island, but everyone is too busy enjoying themselves to listen to what he has to say. It turns out that Mertle is the only one available to help Stitch, and at this point, she's desperate enough to hang out with anybody, so an unlikely alliance forms.
586 stomps through the town, eating cars and terrorizing citizens. Stitch shows up with Mertle in his red car, but apparently, Mertle was not aware that "hanging out" actually meant "fighting a giant monster." Stitch proves to be no match for 586 as it begins to grow even bigger, so the two retreat in Stitch's flying car.
Unfortunately, they are immediately hit by a tractor beam and teleported onto Gantu's ship. Gantu had tried to capture 586 but got Stitch's car instead by mistake. Mertle recognizes Gantu as "that guy who tried to steal Gigi",note but also commenting on the dorky mustache that 625 had drawn on him earlier. Stitch and Mertle are whisked away into containment pods as Gantu follows 586 in his ship.
Meanwhile, Lilo and her new friends are still enjoying themselves at the fair, but that quickly changes when 586 (now absolutely massive) begins rampaging through the festival, with Gantu's ship not far behind. Lilo tries to get the three girls to help her save the day, but they just say that Mertle was right about Lilo being weird, and effectively chicken out.
Meanwhile, Reuben has been left to guard Stitch and Mertle as their new prisoners, and Mertle compliments him for the mustache prank he pulled on Gantu earlier. After Mertle butters him up a bit, Reuben offers to show Mertle a new prank he's been working on in the other room. He opens Mertle's containment pod, and naturally, the first thing Mertle does is immediately pick up Reuben and lock him inside her containment pod. She releases Stitch and they both make their escape.
Lilo loads a bunch of chicken legs into a nearby medieval catapult and launches it at Gantu as he is flying the ship. Unable to see, he ends up crashing the spaceship, letting Stitch and Mertle get off the ship in their red car. 586 immediately picks up said car and Stitch bails with Mertle in tow moments before they are devoured. Stitch tosses Mertle onto a nearby tent so she can hide safely from the danger, and begins to fight the monster. Meanwhile, Gantu begins to chase Lilo, seeking revenge for all the "poultry projectiles" she threw at the ship.
Stitch gets on a horse and starts jousting toward 586 in an attempt to stop it. He picks up the bulky experiment and throws it into the ocean, but unfortunately, it can swim. Stitch is quickly overwhelmed as 586 swallows Stitch whole and begin to chew on him, eventually spitting him back out. Horrified, Lilo has no choice but to make a deal with Gantu — he can have the experiment as long as he can get it away from Stitch. Pleased that there was finally an "abomination" too chaotic for Lilo and Stitch to handle, he gets back on his ship, locks 586 into a tractor beam, and flies away.
Stitch tries to go after them, but Lilo tells him it's okay. She'd rather lose an experiment than lose her best friend.note She also apologizes for getting carried away with her new friends while mistreating Stitch, and the two hug it out. Meanwhile, Mertle sees her friends again, who promise to ditch Lilo and be more loyal to Mertle as long as they get to do other things as a group besides play dolls. It seems that everything is back to normal again, for better, and for worse.
Experiments who were featured or were mentioned in this episode:
- Gigi (X-007): Does not show up, but Mertle mentions her when she recognizes Gantu.
- Tank (X-586): This episode's Monster of the Week; an orange armadillo/bulldog-like experiment who eats metal and grows bigger with every bite.
- Reuben (X-625)
This episode contains examples of:
- An Aesop: It's important to have new friends, as long as you don't neglect your old ones.
- Attack of the 50-Foot Whatever: Tank becomes so huge that even Stitch cannot defeat him.
- The Bad Guy Wins: Gantu gets the experiment at the end because Stitch couldn't defeat such a huge experiment, forcing Lilo to make a deal with Gantu as a result.
- Edible Ammunition: At one point, Lilo uses a catapult to launch fried chicken at Gantu's ship, causing him to crash land as his windshield gets covered in chicken and grease.
- Guest Star: "Weird Al" Yankovic voices a singing minstrel.
- Hope Spot: Stitch eventually grabs the huge Tank and throws him into the ocean to seemingly defeat him... but then Tank grows out of the water, eating wrecked cars that he found at the bottom.
- Idiot Ball: Gee, Gantu, have you ever considered just walking back through those curtains instead of letting yourself be trapped by the sword jugglers in front of you? Oddly though, this doesn't negatively impact him in the end.
- Make My Monster Grow: Every time Tank eats metal, he grows bigger.
- Renaissance Fair: More specifically, an Elizabethan Fair is the main setting of the episode. Also, yes, Hawaii celebrates fairs about medieval Europe.
- Title Drop: Averted; because Lilo and Stitch did not capture 586 in the end, the experiment's name is never mentioned.
- Tractor Beam: Gantu decides to use his ship's beam because he rightly predicted that the experiment would become too big for a containment capsule. Although it takes a while, he successfully uses it in the end.
