At Moe's Tavern, Moe informs Homer and his friends that one of them must be a designated driver (because they are responsible for 91% of the accidents in the city), and Barney loses the choosing draw. While Barney drives the drunken men home in Homer's car, Homer allows him to use it to drive himself home, expecting Barney to return it the following morning. In his distressed state, Barney disappears with the car. Two months later, Barney returns to Moe's Tavern, unable to recall where he left the car or anything else that happened over the previous two months, except for the guest lecture he gave either at Villanova or on a street corner. Homer later receives a letter from the New York City government, which informs him that his car has been found parked in the center of the World Trade Center plaza. Homer reveals to the family that he had once been to New York before when he was 17 years old and had a horrible experience (People and a police officer stole his things, Woody Allen dumped his garbage on him and he got chased by a pimp after throwing a banana peel on him and adding insult to injury, the C.H.U.D.s attacked.). Marge and the children persuade Homer to go retrieve the car and he reluctantly agrees.
Near the end of the bus ride into New York, the family wakes up to find themselves in the city. During that time, Marge points out landmarks to the kids, Homer accidentally kicks a man's legs, and Bart mistakes a group of Hasidic Jews for ZZ Top. When the family arrives in Manhattan, they decide to split up in order to allow Homer to retrieve the car, while they tour the city. Upon arrival at his car, he discovers it has been issued many parking tickets and has been wheel clamped. While waiting for parking officer Steve Grabowski to come remove the clamp, Homer leaves the car to go to the restroom at the South Tower’s indoor observation deck. Homer discovers that it is out of order and must go use the restroom at the top of the North Tower. While he is doing that, Grabowski arrives at Homer's car. Finding no-one present, he issues another ticket and leaves; Homer's subsequent "D'oh!" echoes across the city. Meanwhile, the rest of the family tours the Statue of Liberty, Little Italy, China Town and the Empire State Building. Bart leaves the group to visit the offices of Mad magazine, and is in awe when he sees Alfred E. Neuman. The family attends a Broadway musical about the Betty Ford Clinic, and then take a carriage through Central Park to where they are planning to meet Homer.
Upon returning to the car, Homer realizes he must make it to Central Park to find his family and leave. Ignoring the wheel clamp, he tries to accelerate and in the process destroys the car's fender. Homer stops by a road construction crew and steals a jackhammer so he can use it to remove the clamp. The car is free from the clamp, but further damaged as a result. Homer flees after being shot at for stopping traffic, then races to Central Park, interrupting picnics and a basketball game, and reunites with his family. While driving back to Springfield, the family reflects on their wonderful time, while Homer's hatred for New York remains.