A day spent with Aunts Patty and Selma at the DMV leads to a fake ID for Bart and a cross-country road trip for his friends. With Bart's sparkling new driver's license and $600 Martin Prince made in the stock market, Bart, Martin, Milhouse and Nelson rent a car and hit the open road. Their plan is check out the World's Fair in Knoxville, Tennessee, but when the kids get there, they discover that the fair ended about 14 years earlier. While Bart and the boys are away, Lisa begins spending a lot of bonding time with Homer, even having sleepovers at the Springfield Nuclear Power Plant. After Bart's rental car is destroyed, the boys are trapped in Knoxville. Only Lisa can save the day, but she needs to enlist the help of her new best buddy, Homer, to get them back home .
