This episode was a real turning point in the series. Better animation, more characters, and stronger story lines. Hilarious and well written episode.
The espisode starts off with the boys going into fourth grade with a new teacher, Ms. Choksondic. Cartman becomes nostalgic and sings a hilarious candy-land type song about third grade. The boys then enlist two star-trek obsessed geeks to build them a time machine.
The plan goes awry and Timmmy is plunged into an out of control wheel chair ala "Speed". The rescue attempts fail and Timmy is taken back to a hilarious pre-historic scence.
Meanwhile, Ms. Choksondic is baffled about teaching the childern. She decides to seek Mr. Garrison in his mountain fortress. And in a hilarious homage to The Empire Strikes back, learns the secrets of teaching in South Park.
In a homage to "The Christmas Carol" and "Empire" Garrison finally admits that he is gay.
The boys come back to class and realize that the third grade wasn't all that great and that life is about change and facing new chalenges.