I absolutely love Jimmy Neutron. I watched it all the time; it's a part of my childhood. They had plans for a season four, but because The Ant Bully failed in theaters and Planet Sheen negatively received with low ratings, the odds of Jimmy Neutron coming back for season four are slim to not happening.
These are the details for season four overall story.
- The premiere episode would've featured Jimmy and the rest of his class teaming up to stop Evil Jimmy and the rest of their evil clones, who have escaped from the Dark Matter Dimension during a class field trip to an asteroid.
- An episode about Cindy, Libby and Betty getting stuck in Jimmy's lab.
- Jimmy and Cindy permanently ending their fighting and rivalry.
- New and more dangerous villains.
- Jimmy's friends getting enemies of their own.
- Nick becoming part of the main cast again.
- Brittany becoming a main character.
- The series finale would've been about all the members of Team Neutron fighting the now-rebuilt League of Villains.
There is a petition here on Change.org demanding the series be rebooted for a fourth season. I signed the petition a while ago. In order to have this petition be sent to Nickelodeon, 20000 signatures are needed and it currently has as of 9/26/17 just over 2500 signatures. If you want Jimmy Neutron to come back, sign this petition and get other people to sign as well.