Warum, zum Kuckuck, können Hosen eigentlich nicht selber gehen? Das fragt sich kein Geringerer als Superhirn Jimmy Neutron. Nach einigem Tüfteln hat der Mini-Einstein einen „Chip“ entwickelt, der seine Hosen selbständig macht. Jetzt tragen sie ihn. Doch es dauert nicht lange, da bahnt sich eine Hosen-Revolte an, und eine ganze Armee von cleveren Beinkleidern bedroht die Stadt Retroville. Was tun?

Clever sein ist ganz schön anstrengend. Deswegen entwickelt Jimmy ein Gerät, das in der Lage ist, seine Intelligenz zu reduzieren. Und Jimmy wäre nicht Jimmy, wenn seine neueste Erfindung nicht auch funktionierte. Der neue Jimmy ist ein ganz normaler Junge, etwas einfach gestrickt, aber glücklich. Doch wer soll Retroville retten, als plötzlich ein riesiger Komet auf die Stadt zurast?

Miss Fowl's class has a candy-selling contest, with the grand prize being a trip to Retroland! To beat Cindy in the contest, Jimmy invents a robot programmed to sell candy no matter what.

In his lab, Jimmy constructs the perfect little brother he never had, "Brobot".

To settle an argument with Cindy, Jimmy brings Thomas Edison to school.

Jimmy goes 15 years into the past to a time when his parents were swinging sweethearts.

Jimmy and Cindy are forced to collaborate on a science project involving hidden treasure.

Jimmy invents the Dream Injector 5000 and enters Carl's dream to figure out what he is afraid of.

Jimmy's attempt to cool off the summer heat wave results in a new Ice Age.

Jimmy, Carl and Sheen form a band in order to beat out Cindy and Libby for the talent contest first prize.

To get revenge on Cindy for winning a race, Jimmy adapts his running shoes so he can move at lightning speed.

Jimmy comes up with an invention that allows him to read Cindy's mind.

Jimmy tries to disprove Nick's scary tale about the Phantom of Retroland.

Jimmy's teleporting goof-up leads to him switching heads with Carl's pet hamster.

When the old tyrant of a hall monster leaves, Jimmy is picked as his replacement.

In order to get his new chemistry set right away, Jimmy hypnotizes his parents.

Jimmy comes up with a snack that is even tastier than everyone's favorite.

Miss Fowl swallows a seed from Jimmy's DNA-accelerated spinach plant turning her into a 50-foot plant.

Jimmy creates an electronic bodyguard to protect him from a bully.

Sheen's oldest and most prized UltraLord is missing! It's up to Jimmy, playing a high-tech Sherlock Holmes, to find it.

Jimmy creates a "get out of school sick" patch.

Hugh takes Jimmy, Sheen, and Carl on a camping trip into the wilderness, allowing no technology whatsoever. So what will save them when a big problem comes along?

Sheen and Carl convince Jimmy to throw a party when his parents go out to watch Ducks. But when Hugh and Judy come home early, how can Jimmy convince his guests to leave?

Jimmy uses his Neutronic Game Cube to send Sheen into his favorite Ultra Lord video game.

Jimmy lands the spot of host on Lindbergh Elementary's Public Access show! When the show fails miserably, Cindy and Libby are brought in as producer and co-star, changing informative Science With Jimmy to flashy Funky Jam Dance Party (with some science).

The mad Professor Finbarr Calamitous schemes to make Jimmy his "scientific slave."

At the parent-child picnic, Jimmy gives his dad a bionic sweatband to help their team beat Cindy's.

Jimmy is hosting a sleepover with Carl and Sheen! To make it the best slumber party in history, Jimmy invents a machine to make perfect pillows for pillow fights, create made-to-order pizzas, and tell scream-your-head-off scary stories. But what happens if the invention is overloaded and the programs mix up?

The Father's Day talent show is a few days away so Jimmy invents a device that turns dorky Hugh into the coolest dad in Retroville.

Jimmy, Carl, Sheen, Cindy, Libby, and Goddard blast off into space in Jimmy's newly invented spaceship to mine for aster-rubies while fighting off space bandits and their own greed.

Jimmy invents the Quantum Replay 9000 which enables him to go back in time. Hugh accidentally sends Jimmy, Carl, and Sheen back 200 million years.