Dexter falls victim to one of his own inventions and sends Dee Dee back in time to warn his past self about the consequences, but the past Dexter proves hard to convince.
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.
Dexter and Dee Dee’s father buys a video game for them to play, but the game sucks Dexter inside when he plugs in the cartridge, and it is up to Dee Dee to bring him out.
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’s school and parents decide to send him to college. He ignores his fellow students, who prefer to “party now, study later”, until his mind finally snaps from the workload.
When Krunk gets a tortilla chip stuck in his tooth, Major Glory decides to fix it by pulling the tooth out himself against Valhallen’s admonition to take him to the dentist as they have the tools to take the chip out properly.
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.
With only one television in their apartment, Major Glory, Krunk, and Valhallen disagree on what to watch: Major Glory’s televised capture of the Disgruntled Postman, TV Puppet Pals, or the monster truck pull.
In need of an assistant to operate his latest invention, Dexter performs a brain transplant on Dee Dee to make her smart enough to fulfill the role. With her new brain, Dee Dee proves to be more intelligent than Dexter.