Humour, mistaken identity, and massive confusion reign when Jimmy Neutron and Timmy Turner (The Fairly Odd Parents) inadvertently wind up in each other's worlds in this double length episode. Timmy Turner's wish to visit the greatest laboratory in the universe lands him in Jimmy Neutron's backyard lab just as Jimmy is about to give his cyberdog Goddard a tuneup. When Jimmy accidentally teleports himself into Timmy's bedroom with a gizmo created by Timmy's Fairy Godparents, Cosmo and Wanda, Timmy interrupts Goddard's reprogramming by booting up a violent video game that severely changes the dog's disposition. Thanks to some restylization, friends, parents, and teachers mistake the new big headed, bumpy, computer animated Timmy and small headed, spindly armed, cel animated Jimmy for one another. Crazy predicaments abound, including a budding romance between Cindy Vortex and Timmy and a much-awaited trip to Fairy World for Timmy's teacher, Mr. Crocker. In the end, Fairy World's very existence is threatened and a monster Goddard seems destined to destroy Retroville. Can some heartfelt wishing and a good brain blast get the two parallel dimensions back on course and put Jimmy and Timmy back in their own worlds?