Dexter travels to Mars to find intelligent life, unaware that Dee Dee has stowed away in his space capsule. After Dee Dee gets covered in red dirt, Dexter thinks she is a real-life Martian.

Dexter brings the cavemen who first discovered fire back from the past, who acts like Dee Dee and starts smashing the lab.

Dexter’s father tries to watch a golf tournament, but is constantly interrupted by his wife, Dexter, and Dee Dee.

When Dexter catches Dee Dee killing ants, he shrinks them both to take her inside an ant colony so that she can learn how organized the ants are.

Dexter and Mandark drill underground to expand their labs, but end up running into each other’s work. So they agree to share the lab, inducing chaos.

Dexter’s lab is threatened with repossession unless he can repay his debt to NASA. When Dee Dee wins the same amount in a lottery, he decides to steal her money out of desperation.

When Dee Dee’s Judo skills prove too much for Dexter, Dexter learns how to fight back at the same dojo she went to.

Dexter travels to the moon and finds that aliens are planning an invasion on Earth, and he uses his Robo-Dexo 2000 to stop them. It turns out that they only were interested in purchasing sweaters for the winter.

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.

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.

Dexter’s mom fights another woman at the supermarket for some new latex gloves.

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.

Dexter’s father tries to get himself and Dexter to his fishing spot before sunrise so that they can start fishing before others arrive.

Dexter creates the ultimate robot to replace his Robo-Dexo 2000.

Dee Dee builds a tree house and allows everyone inside except Dexter, in revenge for the times he kicked her out of his lab.

When their father makes Dexter and Dee Dee switch rooms, Dexter believes that Dee Dee is destroying his lab and destroys her room in retaliation.

Major Glory forces Krunk and Valhallen to tidy up their apartment for his Uncle Sam, who is coming over for a visit.

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.

Dexter becomes the stern administrator of his local library.

After Dee Dee steals his critical invention, Dexter ventures into her room to find it.

Dee Dee enters the land of her imaginary friend Koosalagoopagoop.

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.

Mandark gets in touch with nature.