Fourth in a set of Nickelodeon series crossovers, it's science vs. magic as Timmy Turner who's destined to fail at science class wishes he had the greatest lab in the universe, which just happens to be the not-so-secret lab of Jimmy Neutron. Timmy and Jimmy are teleported to Retroville and Dimmsdale respectively, where Jimmy was planning to upgrade his mechanical dog Goddard, only to have Timmy download a video game that's far more violent than even it's manufacturers expected, and somehow wins the heart of Cindy Vortex. Meanwhile, Jimmy's effort to return to Retroville has been thwarted by fairy-mad teacher Denzel Crocker who uses Jimmy's scientific knowhow to take over Fairy World.