Bart lectures the other students on the bus on the topic of water balloons. After hitting Lisa with one she fights with him all the way home. Marge stops them and tells the pair that they are going to Ohio to celebrate Uncle Tyrone's birthday. Bart and Lisa are saddened with the idea: they get to stay home. As a family activity they all rent a film; Bart and Lisa are depressed 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 children. At the airport, they see people in another queue, dressed in Hawaiian shirts and skimpy tops, going to Miami. On a whim, they decide to forego the visit to Uncle Tyrone and get on the plane to Miami as a second honeymoon.
Lisa and Bart are watching TV with Grampa, when they learn that the hotel in Dayton where Marge and Homer are supposed to be staying has been completely wiped out by a tornado. They suddenly get a call from Marge, informing them that all is well: "Just checking in." Suspicious, Bart uses last-call return to find out the last incoming phone number and discovers their parents are in Miami. They get Grampa to take them there. Homer and Marge see the children waiting for them outside their hotel room door, so they run away again, but Bart and Lisa are on their trail. They will not have any trouble paying for their chase, considering Homer has borrowed Ned Flanders' credit card and Bart has borrowed Rod Flanders' credit card. Meanwhile, in Miami, Grampa found companionship with an old man named Raúl who responds by turning his hearing aid off.
Homer and Marge are in Atlantic City when they spot the children once more, so they go on the run from them in an instrumental musical montage and an animated sequence. Homer and Marge finally find themselves at the Niagara Falls, but the children are there as well. Bart and Lisa confront them and Homer and Marge finally give up and allow the children to stay with them. The children start to mess about in the room, making Homer and Marge even more despondent.
That night, Bart and Lisa, feeling a little guilty, decide to give their parents their space and go to an amusement park, only to find their parents are already there. Homer and Marge, thinking the children are chasing them again, run from the pair to find refuge in a giant inflatable castle, which their lovemaking antics cause to fall into the Niagara River. The rescue teams who are Canadian and American start to fight over who is to rescue. The couple floats towards the falls and certain death, only to be saved by their large flotation device. Later they pass by the Maid of the Mist, whose captain asks them if they need help. Homer and Marge shout they do not need any from inside the inflatable castle, as it floats away, and they engage in sex underneath The Falls. Bart and Lisa, watching from a telescope, decide that everything worked out all right.
Later back in Springfield, Ned and Rod Flanders receive their monthly credit card bills and gasp at the charges Homer and Bart have run up.