T.J. was growed up as a men when worlds collide and created the universes of the dimensions. They can try to save the third street, from a murderer ex-teacher whose plans (though inaccurate) are to turn third street into an antarcticopolis so that children can be slained and sacrificed to stay outside, inside and survive, thus improve their grades cancelled forever.
As the next recess of the march 14 year takes place at Third Street Elementary School, the Recess Gang plots one testing Vandal Savage holds the toy gun on the school. Spinelli moves the jeep around at the school, and she, Vince, Gus, and Mikey catapult all the ice cream they smuggled from the roof of the school. As Ms. Finster rushes out, Principal Prickly has the rejoyful plan to make kids go on the field trip to the african safari, and T.J. uses Gretchen speaks to Principal Prickly that shows up and takes T.J. to the bus. but then it was the african safari that The Wild Thornberrys live in the savannah waiting for Prickly to come down, as there are only mere minutes before the final bell of the school year rings.
Now that school's field trip finally begins to the Africa, T.J. and his friends, Prickly, Finster and new friend, Francis are excited to get started on their vacation. However, T.J.'s happiness is short-lived when he finds out that he and all five of his best friends (and later, most of their schoolmates) are going to be spending most of the field trip camp are various camps around the state to improve their skills. T.J. happily to see his body transformers that can grow up or down machine out of his pocket, he creates the body, pushes the button transforms himself into the men, rides his bike around the jungle to meet Eliza Thornberry, doing things by himself, when he notices that there's something going on at the den of the lion's den. He meets inside and finds a lions family groups when it's safe. Panicked, he is gonna to tell his friends, teachers, Prickly and the students that the nazis stolen Darwin forever, but no one believes him that takes him, Eliza and us to Third Street. When he they've traveled back to third street to come to see what's going on, he is dematerialized when he saw Scorpion from Mortal Kombat is approaching, that has his brother Sub-Zero defeated him. T.J. uses Mario & Luigi became friends into driving to all the camps to pick his friends up.
Adult T.J. that has the facial hair and his friends sees the school grounds at night and looked at Darwin kidnapped by Nazis from the moon to hold a crate of documents, when they find it filled with Weather Maps, Supply Scores, Taco Tuesday, and other boring information, they concerting him of inventing a plot to bring them back. They are about to head back to their camps until they see the tractor beam come out of the school's roof and shoot out a green laser to steal the people as prisoners and the buildings and are shocked to see it. They agree with T.J. that something is going on with Darwin and other people of Third Street arrested by the Vandal Savage and Phillium Benedict and they need to find Prickly since they have no proof.
Back at Third Street Elementary School, T.J. interrogated by Vandal Savage, but he realize that Phillium Benedict or Emperor Sacrifice turns the Third Street School into the nazi world called the winter town as Antarcticopolis, an alien creature had frozen, and the others are worried that they could be discovered missing from their campsites. But T.J. sentances to death with the lava crane thrower for them. As they stakeout the school; the Justice League: Superman and his friends saves T.J. from the dead and takes them to Principal Prickly, and then takes Darwin out of school back to Eliza.
On the Janitor room at the school, T.J. and his new friends captured with Luigi & Mario and the others that has called the Master of Cartoonists, including George Washington, Sir Lancelot of Camelot, Kayley and The Wizard. T.J. gets rid of the gag and the rest of us are met by a man named Dr. Phillium Benedict, who is revealed to be the mysterious man talking to the scientists.
After Benedict, Savage and their nazi army leave, Prickly relates to T.J. how, back in the spring of 1968, he and Benedict were best friends. The latter became principal of Third Street School and, during a private conversation with Prickly, revealed that he intended to move to abolish the kindergarten to improve the grades has been shutted down and further his battle to war. Benedict was criticized by the parents for it but refused to back down and Prickly went to the superintendent as a means of convincing Benedict to change his mind. The superintendent instead arrested Benedict who still wouldn't change his mind and promoted Prickly to the rank of principal. Benedict's girlfriend, Muriel P. Finster, broke up with him, driving Benedict into a hateful vengeance. Later, Prickly says, Benedict went on to become Nazi Counter Intelligence but he was arrested by the U.S. President when he tried to abolish Third Street, only this time it was alien invasion.
T.J., Prickly, Eliza, Darwin and The Master of Cartoonists escape, and then Savage crashed T.J. again. T.J. uses signal on Washington D.C. (in Prickly's drawer) and tells the president about Benedict wants to destroy Third Street Town. T.J.'s friends manage to flee the school grounds and go through the crate of documents again. Spinelli finds a date book that says lunar perigee (which happens to be 12:22 the next afternoon) on it; Gretchen deduces that it's not the laser beam, it's a tractor beam, Benedict is trying to move the people as prisoners and the buildings out and land it into the school and sends it to the prison room using the beam when it is closest to the town. Benedict reveals to T.J. and Prickly that his ultimate judgment is to turn the town into the deadly nazis town called Antarcticopolis so that Taco Tuesday is called the deadly monster gluestick called Kragle will force the people to die.
T.J.'s friends get his sister, Becky, president and the U.S. Army, after convincing her to drive to the camps again, where they pick up the people. Gus draws up the plans and leads a free-for-all battle to attack the school and rescue the citizens of Third Street, Eliza, Darwin, The Master of Cartoonists, T.J. and Prickly. T.J., Prickly and the others escape the cage that Benedict has imprisoned them in and disguise as two of Benedict's nazi troopers. Gus' plan works, and most of the nazi troopers and the nazi officers are knocked out. All the citizens of Third Street pour into the auditorium. Another set of nazi officers protects Benedict as he prepares to pull the lever. As Phillium voices his goals, T.J. points out his plans' flaws but the villain is still intent on going through with them and orders for the beam to be ready.
However, Muriel P. Finster arrives with an army of teachers and other school faculty members and all the earth's careers. After rejecting Benedict again, she brings us in and a fight breaks out. In the chaos, Benedict tries to activate the beam to move the people and the buildings inside the prison room but Prickly punches Benedict though this causes Benedict to slumps. T.J. tosses his baseball to Vince, whose accurate arm destroys the machine. This act saves the day and causes Benedict to bemoan the failure of his plans.
The police (who were presumably given proof of the events) soon arrest the protesting Benedict and his cronies for their crimes. And then Third Street Elementary School becomes the murderers who stoles The Master of Cartoonists. T.J. reveals himself to be brave for Eliza, Darwin and the others and saying goodbye to her. After, Eliza, Darwin, The Master of Cartoonists leaves back to universe, the civilians are lauded as heroes for their success. T.J.'s friends inform him they intend to spend the rest of their tears with him, as they only little time to be kids. T.J. is excited but decides to handle one thing, he rushes into Prickly's office to thank him, only to be thanked by Prickly for being reminded of why he wanted to be an educator. T.J. reverse the man transformation back to normal and runs off with his friends, while Prickly puts on the peace symbol necklace, a memento of his past friendship.
- Andrew Lawrence as Young T.J. Detweiler
- Ron Perlman as T.J. Detweiler
- Rickey D'Shon Collins as Vince
- Pamela Adlon as Spinelli, Dewey Duck
- Ashley Johnson as Gretchen
- Jason Davis as Mikey (Speaking)
- Robert Goulet as Mikey (Singing)
- Courtland Mead as Gus
- April Winchell as Mrs. Detweiler, Miss Finster
- Dabney Coleman as Principal Prickly
- Will Ferrell as Emperor Murderer "Phillium Benedict" Sacrifice
- Samuel L. Jackson as Francis
- Cree Summer as Princess Kayley
- Andy Dick as Fenwick
- Phil Morris as Vandal Savage
- Melissa Joan Hart as Becky Detweiler
- Allyce Beasley as Miss Grotke
- Ryan O'Donohue as Randall
- E.G. Daily as Cap'n Sticky
- Erik Von Detten as Captain Brad
- Paul Wilson as Mr. Detweiler
- Tim Curry as Nigel Thornberry
- Jodi Carlisle as Marianne Thornberry
- Danielle Harris as Debbie Thornberry
- Lacey Chabert as Eliza Thornberry
- Tom Kane as Darwin
- Flea as Donnie Thornberry
- George Newbern as Superman
- Susan Sheridan as Wonder Woman
- Phil LaMarr as Green Lantern
- Crispin Freeman as The Flash
- Kevin Dorsey as Batman
- Tara Strong as Hawkgirl
- Carl Lumbly as The Martian Manhunter
- Ray Romano as Sir Lancelot
- Keith David as Klorn the Lion
- Grey DeLisle as Scawn the Lion Cub
- Robin Williams as Mario & Luigi
- Hugh Jackman as Raiden
- Liv Tyler as Sonya Blade
- Kevin Grievoux as Jax
- Patrick Stewart as The President of United States
- George Lindsey as Colonel Wolfgang
- Harry Shearer as The Announcer
- Joan Cusack as Queen Seville
- Alan Rickman as King Seville
- Leonard Nimoy as The Wizard (Leader of Master of Cartoonists)
- Clancy Brown as Bald Guy
- Tony Jay as Dr. Rosenthal
- Jim Cummings as General Adler
- Ron Glass and Gregg Berger as President's Bodyguards
- Dan Castellaneta, Diedrich Bader, Joel McCrary, Robin Atkin Downes, Keith David, Andre Sogliuzzo as Nazi Soldiers
- Kevin Michael Richardson as Chief Gregory
- Neil Ross, Michael McConnohie and Frank Welker as The Dreadnoks
- Jack Riley, Joe Alaskey and Michael Bell as President's Safari Drivers
- Phil Proctor as The Nazi Scientist
- Shaquille O'Neal as Himself
- Kath Soucie as Counselor
- Robert Stack as The Superintendent
- Jess Harnell as The Thing
- Dan Riordan as Mr. Fantastic
- Jack Black as Human Torch
- Kate Winslet as Invisible Women
- Will Forte as Abraham Lincoln
- Don Novello as Leonardo Da Vinci
- Charlie Adler as Edgar Allan Poe
- Jeff Bennett as Napoleon Bonaparte
- and Scott Menville as Ziporki the Zebra