Now both boys get to spend some time living in each other's three and two dimensional shoes, respectively Timmy has everyone in Retroville convinced that he's a boy genius, while Jimmy gets to hang out with some real fairy godparents. But before Jimmy can find a way to get rid of this strange, annoying kid, he pushes Timmy's Auto Poofer and is instantly transported to Timmy's world. Timmy immediately starts playing with all of the cool inventions that are at his fingertips, much to the chagrin of his disinclined host.

Timmy is magically sent to the secret lab of none other than Jimmy Neutron, the boy with the genius IQ. However, Wanda and Cosmo cannot come along, so they give him an 'Auto Poofer' that will automatically poof him back to his room.

After blowing off yet another science fair project, Timmy Turner wishes for access to the greatest laboratory in the universe, where he can easily get his hands on quick gadget.