En route to a Model UN conference, the Springfield Elementary school bus crashes off of a bridge into a river, and then is swept into the ocean. Otto is carried away by the current, and the children wash ashore on a deserted island.

Meanwhile, Homer decides to start a business on the Internet, but his operation is ultimately bought out by Bill Gates in a very hostile takeover.

After the children fail to find anything edible on the island, Bart swims back to the sunken school bus and retrieves their cooler full of food. The kids agree to ration out the cooler’s contents, but the next morning they find it empty. Milhouse, surrounded by discarded candy wrappers, is accused of eating everything. He claims a monster did it.

With Bart presiding as judge, Lisa as the defense, and Nelson as the prosecutor, Milhouse is put on trial. When he’s found innocent due to lack of evidence, the other kids, displeased with the verdict, turn on Bart, Lisa, and Milhouse, chasing them down, presumably, to kill them. When the kids corner the trio in a cave, they all discover that there is a "monster" on the island—a wild boar. They see a potato chip bag from the cooler and realize that Milhouse wasn’t lying. The kids cook the boar for food, and, at the end of the story, a narrator assures us that the children are rescued by Moe.