|“||This time, it's not a Comedy World.||”|
— The movie's tagline.
It should be noted that this film was originally intended to be the series finale of the show, but due to the success of the movie, and the series overall, the show was renewed for a fifth season. Further episodes that were produced were officially stated to take place before the movie, thereby making this film the "true" series finale.
When PC Guy, Eric, David, and Joey hear about a statue that is supposed to represent Lakeside City, they decide to buy fireworks in order to use them at the presentation. But when everything goes awry and the monument gets demolished, they receive a rude awakening from Principal Walker.
The film opens up with The Narrator and Jacob the Dog heading to the AMC Empire 25 theater in New York City to watch The Comedy World Movie, but The Narrator is beaten up by security for trying to bring a pet in. Ironically enough, Jacob is eventually allowed into the theater, and he sits down to watch the movie.
In the movie, Walker is destroying Lakeside City, but then PC Guy attempts to save the day by wearing a costume that parodies RoboCop. But before anything else can happen, this is revealed to be a dream, as Oscar wakes PC Guy up. PC Guy and Eric go through their morning routines and then they phone the rest of The Lucky 8
The 8 decides they should celebrate their anniversary somehow. However, with it being the last day of school, it seems they may have to postpone the celebration to the evening. At school, there are no classes going on, so the gang begins to hang out in the gym.
In the gym, students are signing yearbooks and passing out flyers. The brochures describe how a statue that will represent Lakeside City will be unveiled that night. David and Joey suggest that should make the unveiling extra special by launching fireworks, and that they should launch them with the Pearson brothers. After what seems like quite a long time, the dismissal bell rings, and everybody quickly exits the school building. The Pearson and Maldanado brothers head to the firework store, and Eric foolishly buys remote controlled ones since they were three cents cheaper.
That night, the brothers are preparing to launch the fireworks. Everybody in Lakeside City arrives to view the statue unveiling ceremony. When the statue is revealed to be of nobody but Principal Walker, Eric drops the remote out of astonishment, and it ends up breaking. The fireworks launch, but they fly straight into the Walker statue, smashing it to smithereens. The crowd then turns their attention to Walker.
Walker successfully tricks the town into trying to KILL the brothers for vandalism, and the crowd pursues them, with the exception of the rest of The Lucky 8 members. They try to stop the angry mob, but Walker gets hold of them and drags them away. Meanwhile, the brothers split up to buy time. David hides in a dumpster, but he gets chased out by Chip. Joey hides in a fountain, and he gets caught by a scuba diver. Eric jumps off of a bed and into a tree, and gets mistaken for a monkey. PC Guy is running down an alley, and he phones everyone to meet at the Maldanado house.
In the panic room of the Maldanado house, PC Guy takes roll call, and is horrified when he discovers Eric is absent, but Eric was just at the fridge eating all the food. PC Guy decides that they need to escape Lakeside City as soon as possible, now that Principal Walker has taken over. Everybody decides to pack lightly, and they carjack Old Man Esmond's minivan that he spent his retirement funds on. Suddenly, it turns out that escaping won't be so easy, as Walker has set a bounty of $250,000 on the brothers to have them killed, and he has hired a group of hitmen to murder the gang in cold blood. The hitmen consist of Edgar, Terry, Liam, and Hal.
After an epic car chase through Lakeside City, they finally lose the group of hitmen by driving across a drawbridge that is opening for The World's Slowest Tugboat Parade. The most trusted and experienced hitman, Edgar, takes this as a challenge, and successfully drives their car through the canal. Meanwhile, Walker constructs a wall around the city...
The next day, the car breaks down at an interstate highway. Luckily, there is a service station nearby. When they enter the main building, they find it deserted, though there is a coupon for a nearby restaurant on the floor. The group fights over who gets it, until Eric realizes that the coupon had expired in 1678, and the restaurant had closed soon after.
Suddenly, Joey spots a car outside, but it's only a mirage. Then, they spot an abandoned camper van, and they decide to sleep in there for the night, but little do they know that they are trespassing on private property. Back in Lakeside, Walker has taken the mayor hostage, and has named himself Ruler of Lakeside, which he subsequently renames Walkerville. Various buildings are demolished to make way for nuclear power plants, including the Pearson residence
The next morning, the gang is chased away from the camper van by an angry farmer, who is holding a pitchfork. They come across a lush forest, and decides to seek shelter there. Meanwhile, the team of hitmen arrive at the service station from earlier, and Liam examines a piece of hair left by PC Guy. Suddenly, an employee laughs at and mocks him for playing with dust. The scene then cuts to aforementioned employee's grave, which says "He got the last laugh".
In the forest, Joey decides to practice a wild bird call, though the awful noise produced by said call causes a mudslide, covering the brothers in mud. A nearby tourist mistakes the mud-covered brothers for Bigfoot, and takes a photo. The flash causes PC Guy to walk into a tree, knocking a beehive down. The bees chase PC Guy into another tree, knocking a hornets nest down. PC Guy loses the angry insects after diving into a bush, but this very bush is the home of a king wasp!
Eric, still covered in mud, joins a clan of gorillas, a lion attacks Joey over a box of Frosted Puffs, and David's attempt to start a fire ultimately leads to the entire forest burning down. Meanwhile in Walkerville, pollution from the nuclear power plants has created a red smog around the city. Paul and Bill watch in tears as their respective restaurants are bulldozed in order to build another nuclear power plant.
At the town hall, the citizens are lined up to get a small bite of a tortilla. Inside, Walker is gloating in victory, stating that he is unstoppable, and soon, he will expand his empire to other parts of the world. Meanwhile, the hitmen arrive at the farm. They are greeted rather rudely by the farmer, who proceeds to mock Hal's weight. The scene cuts to the hitmen stuffing the farmer's body in the fridge.
Elsewhere, the brothers approach a shady and unwelcoming city, and it happens to be nothing other than the town of Clinton Heights. Joey enters a wrestling tournament and nearly wins the grand prize of $100,000, but ultimately does not receive his prize as he did not sign the liability waver with a no. 2 pencil. Meanwhile, David wanders into a dark alley, but gets surrounded by a gang. Fortunately, Eric is there to save him, but then the gang leader weakly says that they only wanted to share their nachos with David.
Then, the brothers spots a rather out of place and nice looking house, where they meet an old woman named Doris, who agrees to let them stay there for the night. However, unbeknownst to them, Doris has a deadly secret: she has a habit of taking in and killing strangers!
Doris then goes into her kitchen to make some dinner for everybody. PC Guy uses the time he has to wander around the house, but he starts to get creeped out, stating "he's seen enough". Right before he can warn the rest of the gang, Eric goes into the guest room and he turns on the TV. Suddenly, it releases some incapacitation gas, and it succeeds in knocking Eric out.
- Andrew Rannells as PC Guy and Service Station Employee
- Josh Peck as Eric
- Tom Kenny as David, Paul, Wyatt and Christian
- Carlos Alazraqui as Joey, Luke and The Farmer
- Heath Ledger as Edgar
- Mike Pollock as Principal Walker
- Erik von Detten as Carver
- Jim Hanks as Dallas
- Gary Sauls as Constantinos and Ollie
- Edward Felker as Jacob the Dog (vocally) and Stanley
- Billy West as Sebastian
- Dee Bradley Baker as The Narrator, Old Man Esmond, Spike, Gurney, Mr. Goodman, Skipper, Snodgrass and Chip
- Patrick Stewart as Oscar
- John DiMaggio as Tony
- Jessica DiCicco as Lola
- Dan Castellaneta as Floyd and Mr. Crawford
- John Leguizamo as Gordon
- Jason Griffith as Travis
- Kelsey Grammer Robert
- Grey DeLisle as Sierra
- The movie's animation is a lot more fluid compared to the original series, with detailed backgrounds, a wide variety of facial expressions, more prominent shading, and smooth character movements.
- The movie first premiered on television on June 18, 2005 at 7:00 PM EST on The WB. The premiere successfully attracted 8.91 million viewers across the United States, making it one of the highest rated animated programs on cable that year.