Backfire is the second part of the 5th episode of season 2 in Dexter's Laboratory. In this episode, Dexter tries to modify the family car in order to make the trip a lot shorter. However, Dee Dee gets involved and chaos ensues.
Dexter is in his lab working on a plan to soup up the family car. After he makes an anti-matter potion, he takes the flask out to the family car out in the garage and prepares to place a drop of the potion on it. A fly interrupts his progress and Dexter shoos it away. Suddenly, Dee Dee enters the garage and gets inside the car. The drop of anti-matter hits the front of the car, turning both it, and Dee Dee, into a Porsche-styled vehicle. Dexter gets in the car, and Dee Dee races down the neighborhood street at high speeds. Dee Dee bounces up and down the streets, much to Dexter's dismay.
Further down the street, Dee Dee sees a herd of horses and she follows them to a racetrack. A race between the horses begins and Dee Dee intervenes by galloping in the same manner as the horses. She sees an ice cream truck and decides to chase it. The ice cream man sees Dee Dee chasing him and he speeds away from her. Dexter pulls out one of his inventions and opens the car lock. Dee Dee turns a corner quickly, causing Dexter to tumble and drop his invention, which slides under the car seat. After the chase, the ice cream man flees and Dee Dee stops at a carnival. She goes onto the roller coaster and rides down it with Dexter hanging onto the car seats. At the top of a hill, Dee Dee eyes a toy store and jumps off the coaster rails and heads toward it. Dexter, having enough of the joyride, tells Dee to turn around and head back home.
As Dee Dee heads back home, she lures several police officers into chasing her home. At home, Mom and Dad wake up and get out of bed and head to the kitchen to make sandwiches. As the siblings arrive home, Dad and Mom see the police officers that was chasing Dee Dee. The chief orders the family to come out of their house. Suddenly, the car starts backfiring and Dee Dee flies out of the exhaust pipe. Everyone starts to laugh.