Jimmy and I Am Weasel's arch enemies Trina Riffin, Diamond Tiara, Silver Spoon, Darla Dimple, Baby Doll, Gwen, Becky, The Interesting Twins From Beneath The Mountain, Berry and King Goobot are from KND, Fosters Home For Imaginary Friends, Grojband, My Little Pony: Friendship is Magic, Cats Don’t Dance, Dexter’s lab, The New Batman Adventures and The Eggpire Strikes Back sends invitations to a collection of Jimmy's previous adversaries so they can join together to get revenge on Jimmy Neutron and I Am Weasel, and destroy them. These villains include Jimmy's nemesis, Professor Finbarr Calamitous, his snobbish, and rude daughter, Beautiful Gorgeous, The Junkman, Jimmy's cruel baby-cousin Baby Eddie, his genius rival Eustace Strych, Grandma Taters and the Space Bandits: Zix, Travoltron, and Tee. The villains spend most of their time squabbling amongst each other; in particular, Tee is disrespected by everyone and Beautiful Gorgeous and the Junkman can't stand each other. '
'Meanwhile on Earth, Jimmy, Carl, Libby, Cindy, Sheen, I Am Weasel, I.R Baboon, Laney Penn, Lucky, Pierre, Mushi Sanban, Numbuh 83, Lizzie Devine, Sally Sanban, Numbuh 3, Katie, Apple Bloom, Sweetie Belle, Scootaloo, Rachel T. McKenzie, Fanny Fulbright, Kate, Allie, Chloe Corbin, Tara Jansen, James "Jet" Horton and Lillian "Lil" McGwire are in the lab. Jimmy is showing off his wormhole generator (which was featured in "Win, Lose and Kaboom"). Cindy notices a containment chamber in which Jimmy keeps his dangerous experiments, the Love Potion (from "Love Potion 976/J ") that makes people fall in love with the first person they see; and N-Men packets, which would temporarily restore their superpowers (from "The N Men".) Jimmy's friends show interest in regaining their superpowers, but Jimmy warns them that they are only supposed to be used in emergencies. Jimmy believes that people cannot change and that they would still use their powers with no control. '
' The League of Villains arrive, and, acting in teams, they disable Goddard, seal off Jimmy's lab, and incapacitate Jimmy's friends by playing music that is impossible to not dance to. Once this is done, they kidnap Jimmy and I Am Weasel with ease, because they have disabled his usual methods of defense. Unbeknownst to the villains and Jimmy, I Am Weasel, Lizzie Devine and Sheen manages to sneak onto the ship before it exits Earth's orbit. '
'The villains laugh evilly at Jimmy and I Am Weasel once they abduct them and hold a short (one minute or so) trial, without giving Jimmy and I Am Weasel a chance to defend himself, and declare him guilty. Sheen breaks in in a poorly thought-out plan to rescue Jimmy, which doesn't go much further than breaking into the room. Jimmy, I Am Weasel, Sheen and Lizzie Devine get taken to a prison cell, where Tee guards them, while the villains argue about what the best way to kill Jimmy is. Sheen tries making friends with Tee, even though Jimmy tells him not to. Jimmy believes that Tee is evil and cannot change, as Jimmy said about the N-Men Packets.'
'Tee warms up to Sheen because the other villains have been disrespecting him, and the two become friends. Tee loans a PDA-like device to Sheen (which contains Tee's diary), which Jimmy uses to contact Carl, informing Carl about the kidnapping and what to do. Carl, following the instructions, takes Carl, Libby, Cindy, I.R Baboon, Laney Penn, Lucky, Pierre, Mushi Sanban, Numbuh 83, Sally Sanban, Numbuh 3, Katie, Apple Bloom, Sweetie Belle, Scootaloo, Rachel T. McKenzie, Fanny Fulbright, Kate, Allie Chloe Corbin, Tara Jansen, James "Jet" Horton and Lillian "Lil" McGwire to the lab, grabs the N-Men packets (unknowingly taking the Love Potion), and drops Jimmy's packet. Cindy sees Jimmy's pictures of Betty Quinlan, his crush, and grows jealous. The three shoot off in Jimmy's rocket to save Jimmy from the League of Villains. Cindy, not caring for Jimmy's instructions (as usual), flies the rocket instead of leaving it on auto-pilot like Jimmy asked. Cindy finds another picture of Betty Quinlan on Jimmy's rocket and grows angry. And they almost get hit by a Plane.'
'Jimmy's parents see the kids take off, and try to see if there's anything they can do to help. They head to Jimmy's lab (which Jimmy's dad thinks is a disco); while there, Jimmy's dad plays around with Jimmy's wormhole generator, and accidentally sends the town back to the Cretaceous Era (previously visited in "Sorry, Wrong Era"). '
'Tee, wanting to help his new friends, helps Jimmy, I Am Weasel, Sheen and Lizzie Devine escape. The five of them use a small escape pod to get off the ship. The villains discover this plot, but they are too late to do anything about it. Fortunately for the villains, Carl, Libby, Cindy, I.R Baboon, Laney Penn, Lucky, Pierre, Mushi Sanban, Numbuh 83, Sally Sanban, Numbuh 3, Katie, Apple Bloom, Sweetie Belle, Scootaloo, Rachel T. McKenzie, Fanny Fulbright, Kate, Allie Chloe Corbin, Tara Jansen, James "Jet" Horton and Lillian "Lil" McGwire arrive. The villains bomb them, and they crash on a nearby planet called Mercury. The villains chase after Jimmy's friends, knowing that Jimmy will turn back to help them, which is exactly what Jimmy does.'
'As Jimmy shows up to help his friends, the villains show up. Jimmy and his friends take the N-Men packets, all except for Jimmy, who realizes he got the Love Potion. They immediately realize that the packets were mixed up, as each of them has someone else's superpowers. Carl gets Libby's invisibility power, Libby gets Carl's belching power, Cindy gets Sheen's super-speed power as well as poor bladder control, and Sheen gets Cindy's super strength and flying ability. I Am Weasel gets I.R Baboon’s ice power. Laney Penn gets I Am Weasel’s gooey power I.R Baboon gets Laney Penn’s heat power, Lucky gets Pierre’s thunderclap power, Pierre gets Lucky’s rainbow breath power, Mushi Sanban gets Numbuh 83’s fire breath power, Numbuh 83 gets Mushi Sanban’s supersonic scream power, Sally Sanban gets Lizzie Devine’s animal form power, Lizzie Devine gets Sally Sanban’s sonic bark power, Apple Bloom gets Sweetie Belle's hooves of pain, Sweetie Belle Gets Scootaloo's yodel power, Scootaloo gets Apple Bloom's laser eyes power, Allie gets Kate's kiss power, Kate gets Allie's thunder power. Rachel T. McKenzie gets Fanny Fulbright's flying power, Fanny Fulbright gets Rachel T. McKenzie's Tornado Generation power, Numbuh 3 gets Katie's dance power, Katie gets Numbuh 3's hands of pain power. Because they're not used to the superpowers, they mess up the attempt to defeat the villains. The villains blow Jimmy into a pit and have Junkman throw a boulder on them. Cindy tries to confesses that she secretly lo- (she isn't able to say anything further than "lo") Jimmy. Assuming she means "love" (which she immediately denies), Jimmy has a sudden inspiration and blows the Love Potion at the villains, causing Beautiful Gorgeous and the Junkman to fall in love with each other. He then takes advantage of the distraction and escapes. '
'Jimmy, I Am Weasel and his friends and Tee ride back to Retroville, only to be sucked into the wormhole that Jimmy's dad created. The League of Villains, now only Grandma Taters, King Goobot, Trina Riffin, Darla Dimple, Baby Doll, Gwen, Becky, Diamond Tiara, Silver Spoon, Baby Eddie, Eustace Strych, The Interesting Twins From Beneath The Mountain, Berry and the two Space Bandits, follows them into the wormhole. Jimmy tries to figure out how to reverse the wormhole while his friends use their superpowers to try to protect the townspeople from the various dinosaurs. The Space Bandits side with them in the process. The villains show up to complicate matters. Fortunately, Jimmy finds a way to fix the forcefield, but does not want the villains to return. He gets a forcefield generator and traps the League of Villains (except the Space Bandits) in the Cretacious Era, while Cindy disables the wormhole, doing so because Jimmy promised to throw out all of his pictures of Betty Quinlan, At the end, Sam lets everybody come to the candy bar. On the way inside, Jimmy and Cindy hold hands. '
Meanwhile in the Cretacious Era, the other villains are cornered by 2 T-Rexes (a.k.a T-rex from Fantasia and Sharptooth) and Baby Eddie drives it away with a 5-day old dirty diaper which makes the other villains grossed out.'