Cosmo and Wanda shrink Timmy so he can complete his assignment on the microscopic universe but problems ensue when Cosmo and Wanda, who have also shrunk themselves, get eaten by Vicky. Timmy must now go inside Vicky to save his godparents but stirs up a lot of trouble in the process. To make matters worse, Vicky plans on tearing apart the house and blaming it all on Timmy to his parents.

Timmy meets his favorite superhero, The Crimson Chin, but the discovery that he is fictional sends the hero into a deep depression. Timmy must now reverse this situation, and as a result, he gains the superhero alter-ego of Cleft the Boy Chin Wonder.

Timmy switches lives with Vicky's dog, but swiftly discovers that the dog actually has it just as badly as he does.

Timmy wishes for everyone in the world to be the same when an evil dentist won't give him his ball back. Problems inevitably ensue, and Timmy can't wish things back to normal as Cosmo and Wanda aren't able figure out who he is.