Dexter’s family goes to the beach, where Dexter tries to communicate with whales. He must rescue Dee Dee (dressed as a mermaid), when she is captured by manic pirates.
When Dexter’s new device, made to help him see through solid objects, fails to work as expected, he ends up seeing through people’s clothes, which puts him in an uncomfortable situation.
Dee Dee’s stuffed animals come to life and roam the house when Dee Dee uses a formula that brings inanimate objects to life, which delights Dee Dee, much to his dismay.
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.
While out for dinner at a pizza restaurant, Dexter tries to slow down the “Whack the Weasel” machine to win a stuffed Monkey doll before Dee Dee does. Security captures him for tampering with the machine, and he falls into the hands of a mad scientist.
Monkey must defend the city from a giant underground lava monster, Magmanamus (Brad Garrett), who cannot sleep because of the noise created by its residents.
After being denied dessert by his parents for not eating his vegetables, Dexter uses radiation therapy so that he can like vegetables, but it causes a severe side effect that turns him into an Incredible Hulk-like character if he goes too long without them.
To fix their apartment’s plumbing, Krunk and Valhallen go to the basement, where they meet Ratman (Maurice LaMarche), a diminutive vigilante raised by rats (a parody of Batman).
Since his studying is interrupting his favorite TV shows, Dexter creates a helmet to absorb the shows directly. However, the plan backfires when he randomly snaps into television-based outrages.
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.
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.
Dexter, Monkey, Agent Honeydew, the Justice Friends, Dee Dee, her imaginary friend Koosalagoopagoop, Mandark, his parents, and Dexter’s parents participate in a cross-country race a la Wacky Races.
After Dexter’s pencil rolls to the back of the school bus, Dexter goes to retrieve it, but legend says that no one has ever returned from the back of the bus.
After watching an Action Hank movie on television, Dexter grows a synthetic beard to try to be cool, but the police mistake him for Action Hank himself.
