"As they say in Missouri, 'I ain't goin' back to Missouri!'"
— Tom Sawyer
Shelf Life is the third episode of Season 4. It is a half-hour special.
Timmy has to complete a book report during summer vacation, but the first day of school is nearing, so Timmy wishes that Tom Sawyer would come out of his book and help him write his book report. Tom, being the lazy swelling type, steals Cosmo's wand and goes into a few well known books and edits them, forcing Timmy, Cosmo and Wanda to follow him and end his antics before Tom re-writes the laws of physics at the book "Astrophysics for Morons".
It's summer vacation, the time for rest, relaxation, fun and excitement. Timmy puts off the assignment until the last minute, on Labor Day. He then wishes Tom Sawyer out of his book to try to make things easier for himself. But Tom caught Cosmo's wand, and he runs amok in various books. Timmy and his fairies follow Tom into the books. The first one is Moby Dick before Tom changed it to Moby Duck which throws Ahab off. The next one is Frankenstein which the villagers attack the monster, then Timmy changes Villagers to "The ill attack" which made them ill. Then, appears is a Frankenstein Monster...Truck. Then, it changes from Monk to Hunk to Skunk. Then, the third one is Tarzan: Lord of the Apes which the title character of the book (in drapes) tells Cosmo who dressed him. Then, Timmy changes Drapes to Shapes. Then, he calls himself "Lord of Shapes" which shows a circle,a square and a triangle. The 4th book is The Three Musketeers which Wanda tries to say "The Three Mouseketeers". The 5th book was Jason and the Argonauts which they fight a creature before Tom changes it from "Argonauts" to "Pussycats" which then titled "Jason and the Pussycats" which the song starts they are trying to stop Tom before he reaches a physics book and turns gravity into gravy and planets into plants. Timmy then wishes that they were in "The Rat in Spats" and that the said book would be on top of the "Astrophysics for Morons" book. Timmy and his fairies arrive before Tom. Tom tells Timmy to beat that, but Timmy says he doesn't have to. The Rat in Spats then appears and explains to the characters that in Spatsville there is only one law: You cannot ever frown. Tom doesn't believe this and starts making fun of Timmy.
As Tom is laughing, Timmy then goads the Rat even more by asking him if he is going to take that insult from a punk from Missouri. The Rat screams at Tom "WHAT DID YOU SAY ABOUT MY SHOES, PUNK?". He then proceeds to squish Tom with his foot. This causes Tom to drop Cosmo's wand which Cosmo then retrieves. Timmy then reveals that he knew that how the story went and by having Tom make fun of the Rat it led to a very big splat. Tom now flattened to death and sent back to his book. Wanda guesses they should revert the books to normal. The 1st day of school began, Crocker says that he graded their book report quickly that's because they are all horrible, he gives AJ an F- for there is no such thing as Moby Dick and there is no whale in this story, he gives Sanjay an F- on his book report for not discussing Jason and the Pussycats, he gives Timmy Turner an A+ on his book report for defeating Tom Sawyer in The Rat in Spats.