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 and Dee Dee enter tryouts to become Major Glory's sidekick. When Dee Dee wins, Dexter realizes that fancy costumes are not the only criterion to become a superhero.

Dee Dee inflates Dexter's hydro-plasmatic suit and constantly floats in the air, prompting Dexter to bring her down.

Mandark doesn't know that his pet duck is really Quackor the Fowl, Monkey's rival. Quackor overhears Mandark talking in his sleep about destroying Dexter's lab and tries to do it, unaware that Monkey is Dexter's pet.

Dexter oversleeps and still has to finish his homework along with getting ready for school and eating breakfast, so he creates a helmet that expands thirty seconds into thirty minutes, but realizes that slowing down time is more detrimental than helpful. When he gets everything done, the helmet shuts off. But Dee Dee blocks his door causing him to miss the bus. When Dexter asks Dee Dee why, she replies "Snow Day, school's canceled!". Dexter realizes he did all that rushing around for nothing!

Dexter accidentally takes a library book without checking it out, so he and Dee Dee try to put it back without being caught.

Dee Dee's new dance annoys Dexter to no end.

Everybody except Dexter gets sick, so he makes himself a plastic bubble to get germ protection.

To avoid the bath, Dexter decides to laminate himself.

When Dexter's favorite show gets interrupted by an emergency, he searches all town trying to find it and solve so regular broadcast returns.

Dad wants to show Dexter the joy of sports.

After Dexter gets bitten by a clown, he turns into one every night.

Dexter and Mandark mechanize the giant figures of Lincoln and Washington from the Mount Rushmore statues and wreak havoc with them.

Dexter creates a small bug that eats all the scrap metal caused by Dee Dee's destruction.

Dexter must save his family after they get possesed by aliens.

Dexter stays at school too much, forcing the janitor to stay as well, so he waits for a day in which Dexter has to leave early for an emergency, as he plans his revenge...

Krunk gets a nacho stuck in his tooth and Mayor Glory wants to take it out himself while Valhallens insists on taking Krunk to the dentist.

Dexter must save Japan from being destroyed by a monster, but his robot must be controlled by four people to function correctly, so Dexter must tell Dee Dee... and his parents.

When Dexter is attacked by Robots hunting "The one who saved the future", he becomes fascinated by the possibility of what he will be in several years time, taking the Time Machine. Dexter arrives in the future where he finds many things have changed...and that his greatest invention holds the key to total tranquility around the world, but in the hands of evil, also holds the key to total domination of the world

No tenemos una sinopsis en español. Ayúdamos a ampliar nuestra base de datos añadiendo una.

When Dee Dee sees an Ostrage at the Zoo, she wants one of her own as a pet.