When his mother falls ill, Dexter creates a robot to do her chores. Dee Dee gets hold of its remote control and wreaks havoc, forcing Dexter to create a second robot to counter Dee Dee’s.
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.
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.
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.
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.
Dexter’s parents discover that he is making false excuses to get out of physical education and now Dexter must pass a physical exam if he wants to pass P.E. and move up a few grades.
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.
Mandark Astronomanov, a new student at Dexter’s school, seems to be superior to Dexter academically. Mandark forces Dexter to shut down his lab so that Mandark’s lab can gain more power. However, with the help of Dee Dee, Dexter manages to destroy Mandark’s lab.
Suspicious that Dee Dee has not entered his lab even once on a particular day, Dexter shrinks himself and enters her room to spy on her. He soon becomes an unwilling character in Dee Dee’s doll story, but he believes the story to be real.
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 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’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.
Dexter is forced to take Dee Dee to the zoo. There, she ends up trying to save an ostrich with disastrous results. Dee Dee and the ostrich switches their places.
Dexter and Koos must save Peepers to keep the land of Kooz from disappearing. However, they must contend with a villain who is determined to make the land of Kooz disappear forever.
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.
Dexter’s father is challenged to an arm wrestling match by a man named Earl at a truck stop. Stunned at the strength of Earl and his determination to beat his father, Dexter attaches a robotic arm to his father to enable him to win.
Dexter accidentally gives himself telepathy that he cannot shut off when trying to overhear his father’s thoughts to figure out what he got for his birthday, causing everyone to accidentally read his own mind.
