Return of the Nanobots is a season 2 episode from The Adventures of Jimmy Neutron: Boy Genius.
Jimmy upgrades his nanobots to correct errors for his poem to beat Cindy's and the nanobots get a new spacecraft. But they are still out of control, and destroys Jimmy's poem, and Jimmy locks them up. The nanobots escape using their lasers and go to their old craft. They follow Jimmy to the bus.
Before that, Hugh ends up with chores by Jimmy and Judy, but makes up an excuse for "Hugh Time". He then goes to his secret garden (or in which he calls it: his workshop) to play and polish his ducks. Meanwhile, in school, Cindy has another poem to humiliate Jimmy. Then, Ms. Fowl asks for Jimmy and Jimmy says that his nanobots messed it up and gets 2 demerits. It's Sheen's turn, but he though Carl said that he was supposed to do an interpretive dance. Carl says that he was supposed to do it Thursday. While Sheen does the interpretive dance, the nanobots see that it was full of errors and help Sheen, in a bad way, and Jimmy is confused how they escaped. He then tells them to stand down, but they see Ms. Fowl and give her a weird haircut. Ms. Fowl runs and the nanobots chase after her. Jimmy, Carl, and Sheen (acting loyal because of the dance) chase after the nanobots. The nanobots lose Ms. Fowl and go look for more errors. The nanobots correct the posture, basketball techniques, and cooking. Jimmy and his friends look for the nanobots and Cindy tells them that they're in the lunchroom. When they get in, they see the nanobots throwing away a kid's lunch. The nanobots then see that Cindy and Libby have horrible clothing and correct it with yarn and scissors. They like it, but Jimmy tells the nanobots that people's flaws make them perfect to make them blow up like last time. The nanobots then get confused and start deleting people because of extreme error. The nanobots lock up Jimmy in a closet and delete everyone except Carl, Sheen, and Hugh. They then see that there are more errored people in the neighborhood, and they start deleting everyone there. Their scanners also detect human errors in the whole world and start deleting people in France. Carl finds Principal Willabee's keys and unlocks the closet. Jimmy and his friends go to the lab. Sheen yells that everyone is gone, but Jimmy explains that their lifeforms are turned into data and put into a virtual trash bin and if it gets full, the nanobots have to delete them permanently.
Meanwhile, Hugh needs wood polisher and finds that there is no one there. He goes to the Weezer's place and sees that no one is there. He checks the whole neighborhood and finds no one. He then thinks that everyone formed an angry mob, and he notices that he's wrong. He then says that he's the only person in the world. Then, he has even more Hugh time. Hugh then finds a truck of Aunt Mo's pies.
In the lab, Jimmy invents a motherboard to stop the nanobots. Sheen and Carl are supposed to be watching the monitor for the nanobots, but Sheen plays a space game and beats his own score (He gets the score of 9999). The nanobots then knock on the door and Carl tries to answer is but wonders who it is. The nanobots says that there is a telegram, Carl doesn't believe it, and the nanobots say that it's a llamagram, and Carl answers it, but gets deleted. Sheen gets deleted and Jimmy and Goddard, Jimmy's robot dog, run away. Jimmy flies over the neighborhood and sees dad with Aunt Mo's pies. Goddard then gets deleted and Jimmy falls, but the nanobots catch them. The nanobots then figures out that the virtual trash bin is full and tries to dump the memory, but Jimmy uses his Brain Blast to think of the endless pie (Aunt Mo's pie) and tells them to not hit the delete button. He then shows the nanobots his poem and changes it. He gives it to the nanobots and it read:
"Cindy sings the body electric / but she's still not as smart as me. / She can't even compute the value of pi / Which I know equals three."
The nanobots go crazy from extreme error and calculate out pi. It comes out 3.14159265358979........ and it goes on forever. The nanobots then explode from too much thinking. Everyone then comes back (with Cindy falling from the sky and people popping up in random places). Hugh is upset that his pies are gone. He then sees Judy and Jimmy and is happy. Judy wonders what is happenning and he makes up an excuse. Everyone is happy once again.