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.