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.
Dexter decides to work with Mandark, but finds himself doing all of the work. In the end, Mandark tries to press the button when Dexter connects the plug in the outlet to bring his show title back.
While out for dinner at a pizza restaurant, Dexter tries to slow down the “Whack the Weasel” machine to win a stuffed Monkey doll before Dee Dee does. Security captures him for tampering with the machine, and he falls into the hands of a mad scientist.
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.
Dexter and Dee Dee listen in on their parents’ conversation; they are playing Scrabble, but the way they talk makes it sound like Dad was cheating on Mom
Not interested in hearing Dee Dee’s long-winded story, Dexter gives her a silencing formula to keep her quiet, but it instead turns her into a giant monster still bent on telling her story. When he realizes that nothing can make her quiet, he becomes a giant monster himself.
Mandark gets inside Dexter’s computer system and creates a computer virus, so Dexter must follow him inside and kick him out from cyberspace. However, Dee Dee has other plans in mind.
When Dexter is bitten by a clown’s dentures, he begins turning into a mad clown every night, terrorizing the town with his mayhem, and only Dee Dee, who knows mime, can stop him.