When Dee Dee takes photographs of his lab, Dexter goes on an adventure to retrieve the photos before his parents see them.

Dexter thinks that a crazy homeless person balancing electronic devices on his head and muttering gibberish is a genius trying to contact aliens, so he takes him home.

When Dee Dee eats a contaminated apple, she turns into a monster every time when she tells Dexter what to do.

Monkey’s birthday party is interrupted by Barbequor (Robert Ridgely), an intergalactic villain who plans to eat the planets, and his sidekick, the Silver Spooner (Rob Paulsen).

Dexter finds the exact opposite of his family, a hyperactive boy who is like Dee Dee and has scientist parents who are like Dexter. Sensing to fit in, he switches places with the boy.

Dee Dee’s father trains her to fight a gang of bicycle-riding rogues dressed as ninjas who target her paper route every morning.

Dexter tries to avoid being pushed into the family’s new swimming pool by his father, since he cannot swim and is afraid of water.

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.

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.

Dexter tries to figure out how Dee Dee keeps entering his lab every time he kicks her out through one entrance and seals it.

Dexter and Dee Dee realize that they make a good team, so they decide to do stuff together, but doing so makes things worse.

Dee Dee teaches Dexter how to live life her way instead of being lonely and purely focused on science.

Dexter’s mother asks him to read a story to a sick Dee Dee. Dee Dee becomes bored of Dexter’s story and creates one of her own.

After fellow Justice Friend White Tiger helps Valhallen stop a super-villain, the latter invites him to spend the night in his apartment, forgetting that Major Glory is allergic to cats.

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 discovers that Beau, Dee Dee’s new boyfriend, has similar interests as him, Dexter tries to steal Beau’s attention from Dee Dee.

Dexter studies the potato, and when he is fascinated by its power to light up a light bulb, he tries to use it as an energy source.

A nature documentary team observes “Blackfoot” (Dexter) and “Slim” (Dee Dee) in their “natural habitat”.

When Dexter’s computer gets laryngitis, Dexter must find a replacement voice.

After a crime prevention talk at school, Dee Dee, Lee Lee, and Mee Mee become crime fighters, but they unintentionally end up being neighborhood criminals.

When Dexter tries to inject himself into an ill Dee Dee to find a cure to the common cold, he accidentally ends up inside his dog, believing that Dee Dee is infected with a dog virus.

When Dexter’s nightmares become frequent and problematic, he invents a machine that allows him to have nice dreams, as long as Dee Dee can operate it properly while she is awake.

Dexter creates a robot to assist him, but the robot starts controlling his lab and tries to destroy Dexter.

Dexter becomes the stern administrator of his local library.