Zack, Cam and Spence turn the clock back in order to get a few extra minutes to work on their class assignment. However, they are sent back in time to 1912. They accidentally bring a student named Jeb McFadden back with them to the present, which threatens to erase both Gwen and the school from existence.
After Zack receives an F- on a physics pop quiz, Spence accidentally downloads a tutorial into his brain and he gradually gets more and more intelligent. When Zack is chosen to represent the school in a physics competition, his friendship with Spence is put at risk.
After using Girl Power deodorant, Zack transforms into a girl. He is extremely annoyed when Cam tries to set him up with Vernon and even more so when he thinks that Cam is trying to steal Sarah away from him.
Zack is depressed that he may not make the Horace Hyde-White baseball team. After he saves his father's life by preventing him from being crushed by a jeep, he develops superspeed and superstrength similar to The Six Million Dollar Man (1974).
When Zack's mother Caroline pays him a visit, she brings a bottle of his favourite soda. When he drinks it, Zack develops the ability to teleport whenever he burps. Cam and Spence become concerned that he may not be able to control his teleportation and may pop to the Moon.
After Zack has trouble deciding whether to vote for Cam or Gwen in the election for class president, Spence suggests that he participate in a sensory deprivation experiment. As a result, Zack is sent to a parallel universe in which there are no colours and no choices.
Zack, Cam and Spence are building a robot named Elmer for the science exhibition. After Zack uses special glasses, he gains the ability to see through Gwen's eyes and learns that she may be sabotaging Elmer.
After Cam and Spence push Zack into Mr. Munk's office, he becomes the assistant headmaster. Using his new authority, Zack decides to turn the school into a kid's paradise. However, Vernon's father Mr. Mantueffel, the head of the board of trustees, threatens to close the school down by the end of the day if things do not improve.
As a result of wearing gloves that Spence designed to play him music video games, Zack gains the ability to play the guitar like a rock star. However, he can only do so in the confines in his bedroom. This poses a problem when the band Scrap Heap wants to hear him as their new lead guitarist.
As the series finale, Zack must learn Romeo's role in order to pass his English theater exam. However, when he has learn nothing, even the story, he finds himself in another dimension where he plays Romeo while Gwen is Juliet, Cam Tybalt and Spence the monk.