Marty and Jennifer are at the golf course when Marty's attempts to hit the ball cause mud to go all over Jennifer. Marty laughs at Jennifer's hair and Jennifer is upset by this. A classmate of theirs stops by and asks Marty if he wants to go with her to the Country Club. After Jennifer storms off, Marty says that since he is now available, he will go.
Marty decides to get a haircut ready for that evening, and goes to the Brown's house to borrow $100. The Browns aren't in, but Marty spots one of Doc's inventions, a haircutting machine. The machine seems to work, but suddenly Marty's hairkeeps changing every few minutes!
The Browns meanwhile have gone to a theme park, but the price is so expensive that Doc and Clara decide to go back to the World's Fair in 1904 where things were a lot cheaper and simpler. Once they have gone, Marty finds Jules and Verne and asks them where their parents are. Once he has been told, Marty heads back to 1904 with the boys to find Doc.
At the World's Fair, P. T. Tannen, one of the stall holders, is not having much luck with his business. When he spots Marty and his changing hairstyles, he kidnaps Marty. Marty is now a sideshow freak in Tannen's stall, and people come to see the changing hairstyles of Marty. Doc and Clara find out and together with Jules and Verne, come up with a plan to save Marty. They pretend to be filming a movie, with Verne as the "director" and Doc and Clara as silent movie-type policemen. The "policemen" distract Tannen whilst Jules sets Marty free. They head back to the future where Doc sorts out Marty's hair, and he decides to not go to the Country Club, instead going to Jennifer's house and apologizing for laughing at her hair.