Beau Tie is the first part of the 1st episode in season 4 of Dexter's Laboratory. It originally aired on November 22, 2002. In this episode, Dee Dee has a boyfriend who has an interest in science and Einstein, much to Dexter's delight.
Mom and Dad are watching as Dee Dee and her boyfriend, named Beau, spending time together. Dexter peeks in and hears Beau talking about the piece of chocolate in Dee Dee's hand and feels delighted by his words. He walks in and interrupts Beau's time with Dee Dee. Beau expresses his interest in science, which amazes Dexter. Dee Dee runs Dexter out of the living room by tossing him to another corner.
Later, Dee Dee and Beau are watching Jerry Cherry's Jukebox Jamboree when Dexter appears with a pitcher of cranberry juice. Dexter and Dee Dee both reach for the pitcher, and the juice ends up spilling all over Beau's jacket. After Beau heads into the bathroom, Dexter and Dee Dee start arguing. Beau interrupts the fight with his Einstein t-shirt. Dee Dee takes Beau's hand and leads him to the basement. She goes to get Lollipop Village, and finds Dexter sitting behind the board game box. Dexter shows a gyroscopic oscillator to Beau, and Dee Dee shows him the board game she wanted to play. She then takes the box and smashes the gyroscopic oscillator with it. Beau looks at what's left of the invention, and ends up choking.
Another argument between Dexter and Dee Dee ensues. Beau's face turns blue, and Dexter attempts to give him CPR, only for Dad and Mom to interrupt him. Beau wakes up from the incident, and Dee Dee hugs him. In Dee Dee's bedroom, she and Beau ask each other questions. Dexter appears from behind the stack of dolls that are on Dee Dee's bed. Dexter tries to leave with Beau, but Dee Dee prevents him from doing so. Dexter then tricks her with a unicorn, which successfully had him leave Dee Dee's room with Beau.
In Dexter's room, Dexter is reading a book about wrenches to Beau. Dee Dee kicks the door open and takes Beau with her. It then becomes a fight over Beau, as Dexter and Dee Dee carry him back and forth. Beau, fed up with the situation, feels terrified of Dexter and Dee Dee and runs out of the house screaming. Dexter and Dee Dee both realize that Beau wasn't cute or smart and go their own ways.