Iron Vegiemon

Matt and the other kids answer a call for help from Gabumon, whose attempts to liberate a village of captive Digimon have so far failed, thanks to RedVegiemon, who is under the Emperor's control.

Synopsis
In the Digiworld, Davis, Cody, Kari, T.K and Tai are helping Digimon escape from the Digimon Emperor's jail. T.K. is suspicious that it was too easy, and he must've planned it like that for a reason. Just before returning home, notices a large tower, and  is then revealed to be one of the emperor's captives. They arrive back in the real world Izzy and Yolei are shocked to find out the others have brought back the Gotsumon from the Digital World. They decide to pose as art sculptures in case anyone comes in the computer class. Izzy asks Yolei to borrow her Digivice as it seems only the new ones can open the gate to the Digital World, and he would like to study it more.

Meanwhile, back in the Digiworld, Gabumon is helping some Gazimon escape from the emperor's jail. He is caught by RedVegiemon and is beaten until he falls off a cliff into the water below. He washes up on shore next to an old television, desperate to find Matt.

At that moment, Matt is performing in a concert with his band. He and T.K. talk after the show, and they meet Davis' sister, Jun Motomiya. They then receive an emergency message from Yolei. She got a message from Gabumon saying that he needed help. The DigiDestined ready themselves to go, but Yolei is unable to because Izzy is still examining her Digivice.

Once in the DigiWorld, Matt reunites with his partner Gabumon. Before going back into the jail, they decide that this might be part of the emperor's plan, and much to Davis' dismay, that they should rescue all the hostages. The kids (and Gabumon) pretend to be captured slaves, while their partner Digimon pretend to be the ones who captured them. They easily gain access from the Vegiemon and escape from the cell they are put in, but are once again caught freeing Digimon.

When they are trying to escape, Davis begins to lose his temper again because no one listens to what he has to say, and he also gets mad about T.K. and Matt meeting his sister. This makes Matt mad, saying that he needs to learn more respect. Kari also gets mad because Davis was trash talking his sibling, and he becomes upset because he thinks Kari hates him. The Vegiemon catch up to the group and then begin attacking them. Their Digimon are unable to Digivolve because their partners are constricted by the Vegiemon. Veemon gets beat repeatedly by RedVegiemon, and Davis is struggling, frustrated that he is unable to help. Gabumon is also unable to Digivolve because apparently Digimon cannot Digivolve naturally because of the Control Spires. While beating Veemon, RedVegiemon accidentally destroys the nearby spire, and thus Gabumon is able to Digivolve into and with the help of  they defeat RedVegimon. Tai, Izzy and Yolei arrive with their Digimon and realize that the Control Spires power the Dark Rings. Armor Digivolves to and finishes destroying the Control Spire to free all the nearby Digimon from the emperor's control. The DigiDestined deduce that they have to destroy the Control Spire for any particular area to disable the Dark Rings in said area. Luckily enough, Izzy has found a map of the Spires on Yolei's Digivice, one which they can use to help with the task.

Digivolutions
(Number indicates order of occurrence.)

Quotes
Tai: "I can practically smell the cafeteria from here." Davis: "That's my peanut butter and jelly bean sandwich I've had in my pocket since last week." Cody: "Yuck."
 * —Davis probably hasn't washed those pants in a while either.

"How do I get myself into these things?"
 * —Gabumon reflects silently on his capture by the Digimon Emperor.

"Are you crazy, bringing the Gotsumon back from the Digital World?!"
 * —Izzy would never have gone along with that plan if he'd been with the group.

Yolei: "But how are we going to explain it if Mr. Fujiyama comes in here?" Cody: "Don't worry. I'll tell him I'm taking a sculpting class and these are some of my early masterpieces." Yolei: "'Early rejects' might be a better phrase."
 * —Yolei doesn't think much of the Gotsumon as art subjects.

"For trying to escape, you get to smell my roots, and I have root rot!"
 * —RedVegiemon punishes Gabumon and the Gazimon.

"My fur is dry clean only!"
 * —Gabumon after being thrown into the river.

"Man, I stink."
 * —Gabumon ' s wet fur creates a wet dog smell.

Matt: "Listen, T.K., just because I have a rock band doesn't mean I can hide a band of rocks that happen to be Digimon." TK: "Well, think about it. Maybe they can be your backup singers." Matt: "They sound too gravelly."
 * —Matt and T.K. try to come up with a solution to their Gotsumon problem.

Jun: "You may not know it, but I haven't washed this shirt in two years." T.K.: "There's not a lot of room." Jun: "I know. I think all boys are cute."
 * —The fateful first encounter with Jun, Davis' older sister.

Gatomon: "Why do they call those things on top of the TV 'rabbit ears'? Why don't they call them 'cat ears'? After all, when was the last time you saw a rabbit sleeping on top of a TV?" Kari: "This is what you think of?"
 * —Gatomon being random.

Davis: "I can't even believe you're not worried about Kari's well being, T.A.!" T.K.: "T.A.?" Cody: "He forgot how to spell T.K.!"
 * —Cody teases Davis on his mispronunciation of T.K. ' s name.

"Easy there, junior. You have to learn fighting's not the only answer. It should only be your last resort."
 * —Matt lectures Davis about making a smart plan of action.

Davis: "Why won't anyone listen to me?!" Veemon: "What'd you say?"
 * —Davis is frustrated that the others won't take his leadership role seriously.

T.K.: "Come on, Matt, don't fight. He's younger than you are. He doesn't know any better." Matt: "I don't care how young he is. He'd better learn some respect."
 * —Matt ' s probably having fierce flashbacks to his rivalry with Tai as he fights with Davis.

"I can't stand anyone who talks bad about their brother or sister!"
 * —Kari has such a strong bond with her older brother that it shapes her opinion of other sibling relationships.

"I'm gonna make vegetarians around the world proud!"
 * —Veemon decides to take on RedVegiemon singlehandedly to cheer up a depressed Davis.

Veemon: "Put me down or I'll toss you like a salad!" RedVegiemon: "In case you've forgotten, I have the upper hand here!"
 * —Veemon is one brave little Digimon.

"They're certainly going to need a lot of glue."
 * —Hawkmon sees the cracked control spire.

"Sorry, I forgot to yell timber."
 * —Digmon destroys the control spire.

"Whoa! Did I get married when I was asleep?"
 * —RedVegiemon is free of the dark ring's control.

Greymon: "They don't make control spires like they used to." Tai: "Ha! Way to go, Greymon! You're a one 'mon wrecking crew!"
 * —Tai watches as Greymon topples another spire.

"What?! A spire was destroyed? Must be those meddling kids."
 * —The Digimon Emperor makes a Scooby-Doo reference.

Notes and references
Chúa tể bóng tối, Digimon Kaiser Die schwarzen Türme