In the small town of Retroville, Jimmy Neutron (voice of DEBI DERRYBERRY) is known as the boy genius, although that doesn't prevent other students, such as his archrival, Cindy Vortex (voice of CAROLYN LAWRENCE), from making fun of him, particularly when his various inventions don't always work.
Many times his efforts, such as his latest of putting a toaster satellite into outer space -- with the help of his robotic dog Goddard and his best friend Carl Wheezer (voice of ROB PAULSEN) -- to contact alien life forms, only cause his otherwise oblivious parents, Judy (voice of MEGAN CAVANAGH) and Hugh (voice of MARK DeCARLO), to offer bits of advice to him, such as in this case reminding him not to talk to strangers.
Yet, Jimmy's various creations - such as real pearls and a huge diamond - can't convince his mother to let him attend the nighttime grand opening of the Retroland Amusement Park. Thus, he, Carl and their friend Sheen (voice of JEFF GARCIA) follow the advice of school rebel Nick (voice of CANDI MILO) and sneak out to it any way where they collectively wish their parents would disappear from their lives.
It's while they're gone that the Yokians, some gooey, egg-shaped aliens, have followed Jimmy's satellite signal back to Earth and abducted all of the parents from Retroville to be used in some sort of sacrifice to a monstrous Chicken-like creature.
Although the kids are initially joyous about their parents being gone, they soon miss them. Thus, Jimmy sets out to figure out what's happened. Once he does, he assembles his friends and sets out on an intergalactic rescue mission to free their parents from the clutches of the Yokian leader, King Goobot (voice of PATRICK STEWART), and his royal assistant Ooblar (voice of MARTIN SHORT) before it's too late.