When his family is suffering from the flu, Dexter tries his best to not acquire the illness, but his efforts are thwarted by a sick Dee Dee’s presence in his lab.
Monkey encounters Simion (Maurice LaMarche), an intelligent anthropomorphic chimpanzee who seeks vengeance on humans for turning him into his current state.
On Mother’s Day, Dexter’s mother has her gloves taken by the family so that she can relax and not do housework, but she is unable to adjust to a life where she cannot keep the house clean.
Dexter is disappointed when he ends up at an Amish farm instead of a high-tech farm for summer camp. His attempts to modernize the Amish family do not go well.
Dee Dee accidentally shuts down Dexter’s lab, and he has to power it back. In the process, Dee Dee attempts to keep Dexter from finding out what she really did.
Loading the player... Dexter decides to work with Mandark, but finds himself doing all of the work. In the end, Mandark tries to press the button when Dexter connects the plug in the outlet to bring his show title back.
After Dee Dee declares that she can beat Dexter in any game, Dexter challenges her to a series of games in his lab, though he prefers to win by cheating.
Banned from watching a late-night movie due to his young age, Dexter uses his technology to artificially grow into adulthood, but Dee Dee tampers with his machine, causing Dexter to turn into an old man.
Mandark disguises himself as Dexter’s mom to get into Dexter’s Lab. Unfortunately for Mandark, he now has to deal with Dexter, Dad, and Dee Dee’s requests, which are too much for him.
Dexter has a crush on his teenage babysitter Lisa (Kath Soucie). When he finds out that she has a boyfriend, he sabotages their relationship and accelerates his age by ten years in an attempt to win her heart.
After staying up late at his lab, Dexter oversleeps, waking up one minute before his school bus arrives. With no time to do his morning chores and homework, he pulls out a secret prototype device, which converts his last 30 seconds into 30 minutes.
Dee Dee dares Dexter into building her a giant robot similar to his Robo-Dexo 2000. They then team up to try to save an island’s population from being destroyed by an erupting volcano using their giant robots.
Dexter and Dee Dee’s secret decoder rings hold the keys to joining the Action Hanks and Pony Puff fan clubs respectively, but they interchange the clues by mistake, causing them to switch clubs.
Dexter creates a new type of ink that lets him command people to do whatever he wants. However, when Mandark gets his hands on it, Dexter is the one that becomes commanded.
In a fit of rage, Dexter dumps Dee Dee’s favorite teddy bear into the garbage. An upset Dee Dee begins to behave oddly, prompting Dexter to go to the garbage dump and get it back.
Dexter makes his own Major Glory action figures so that he can join the neighborhood’s Major Glory gang, but gets into serious trouble when the rest of the gang finds out that none of his action figures are original.
Not interested in hearing Dee Dee’s long-winded story, Dexter gives her a silencing formula to keep her quiet, but it instead turns her into a giant monster still bent on telling her story. When he realizes that nothing can make her quiet, he becomes a giant monster himself.
