Bart lectures the other students on water balloons and after hitting Lisa with one he gets into a fight with her all the way home. Marge tells the pair that they are going to Dayton, Ohio to celebrate Uncle Tyrone's birthday. Bart and Lisa aren't thrilled with the idea and get to stay home. As a family activity they rent a video, "Love Story" and Bart and Lisa are bored by it such that they ruin any moment the film might have created for Homer and Marge. Homer and Marge look forward to their trip without the kids and on a whim they decide to forgo seeing Uncle Tyrone and get on a plane to Miami.
Lisa and Bart are aware that the hotel in Dayton where Marge and Homer were supposed to be staying was wiped out by a tornado. Bart discovers there parents are in Miami. They get Grandpa to take them there. While Bart and Lisa find their parents, Grandpa goes looking for companionship. Marge and Homer see the kids waiting for them so they take off again, only Bart and Lisa are on their trail. Homer and Marge are in Atlantic City when they spot the kids so they go on the run from them in an instrumental musical montage.
Meanwhile Abe has found companionship in Miami with a man named Raoul who appreciates his rambling stories. Homer and Marge finally find themselves in Niagara Falls, but the kids are there as well. Feeling a little guilty Bart and Lisa decide to give their parents their space and go to the amusement park only to find their parents are already there. Homer and Marge run from the pair only to find refuge in a giant inflatable castle, which their lovemaking antics cause to fall into the Niagara River. The couple floats toward the falls and certain death only to be saved by their large floatation device. Later back in Springfield, Ned and Rod Flanders receive their credit card bills.