Homer recalls a tense family vacation to the Grand Canyon with the Flanders family. At first, the Flanders’ perfection puts the families at odds, but when they get stranded and Ned and Homer go for help, the families finally bond. 
Homer was trying to make Maggie sleep, but after a few failed attempts, Maggie hinted Homer that she wants to hear a bed time story, so he started telling the story of the Grand Canyon vacation with the Flanders. The story took place two years ago in 2014, with people from the church volunteering to clean skid row on a saturday. At the end of the cleanup, Ned Flanders won a family trip to the Grand Canyon for being the most selfless cleaner. After reading the pamphlet, Ned realized that it was a two family trip. They invited the Lovejoy family, but they convinced Ned to take The Simpsons with them.
At the canyon, everyone is astonished by the view, but the two families are not getting along very well. Marge is angry at Maude because she thinks that Marge is not a good parent because of Bart and Homer's shenanigans, and the Flanders are annoyed for the same reason. During a donkey trail, they are passed by a group of millionares that use the canyon at their own wish. Later, the tour guide's donkey fall off the cliff with most of the supplies, leaving both families stranded in the canyon.
Homer did managed to make Maggie sleep with the story, but Lisa wanted to know what happened next, so Homer continued telling the story. At the canyon, Ned and Homer decided to look for supplies when they found the Millionaires' camping site. Homer convinced Ned to steal their food and supplies and escape down the river using a raft. They managed to reach their camping and surprise everyone with a breakfast with caviar and bacon. Later they were rescued and Homer and Ned talk about their friendship.
When Homer finished the story, it's revealed that Ned was also listening through the window. Homer reminds him that they still owe them a trip. Postcards from lots of touristic places around the world go past the screen, but it's revealed that it's actually a trip to a postcard museum, which ironically, doesn't sell postcards at the gift shop.