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.
Dexter’s father sleepwalks into Dexter’s lab. Dexter discovers this, and now has to escort him out of the lab without waking him up, which proves more difficult than thought.
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.
The U.S. army invades Dexter’s lab under the mistaken impression that aliens are using it as a base of operations on Earth, and Dexter must convince them that this is actually his lab, and also has to keep this a secret from Dee Dee.
After staying up late at his lab, Dexter oversleeps, waking up one minute before his school bus arrives. With no time to do his morning chores and homework, he pulls out a secret prototype device, which converts his last 30 seconds into 30 minutes.
Dexter has a crush on his teenage babysitter Lisa (Kath Soucie). When he finds out that she has a boyfriend, he sabotages their relationship and accelerates his age by ten years in an attempt to win her heart.
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.
When Dexter’s friends become tired of his complicated traps and cheating while playing a role-playing game, they put Dee Dee in his place. She changes the style of play, which annoys Dexter but impresses his friends.
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).
Dee Dee gets a song stuck in her head, which is actually a virus. Dexter and Mom soon catch it, and Dexter has to reverse the effects of this. He succeeds at the end, not knowing that Dad also caught it.
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.
