The Springfield Elementary School Model United Nations club is going on a field trip. On the bus, Bart, Nelson, Ralph and Milhouse are playing a game by rolling fruit to the front. Milhouse rolls a grapefruit that gets stuck under the brakes. When bus driver Otto attempts to press down on the pedal, it squishes the fruit, and juice squirts into his eyes, causing to burn his eyes and lose control and crash the bus off a bridge into the river.
Otto leaves the children behind in an attempt to swim for help but ends up being washed away by the current. It is later revealed Otto is picked up by Chinese fishermen. Otto is excited, thinking they will help him rescue the children, but they actually plan to use him for slave labor below deck. The students, however, swim to a nearby tropical island. Soon an argument breaks out over whose fault it is that they're stranded on a deserted island. As all the kids are yelling at each other, Bart blows on a large conch shell and tries to tell the children that being stranded on an island is just like TV where life is easy and cocktails are plentiful, comparing it to The Swiss Family Robinson, only with more cursing. Reality soon sets in when the island is found to be largely barren and the children lack survival skills. With no food found on the island and no adult supervision, the children rely on snack food retrieved from the sunken bus by Bart. They awaken the next morning to find the snacks all gone. Suspecting Milhouse because of his pot-belly and nacho cheese breath, the students put him on trial and he blames the loss on a mysterious island "monster".
Back at home, Homer discovers that Ned Flanders has his own home-based Internet business, Flancrest Enterprises. Homer complains to Marge that everyone except the Simpson family are getting rich off the Internet, and he wants a piece of the action, despite knowing nothing about it. He launches his own dot-com company, Compu-Global-Hyper-Mega-Net, which is later bought out by Bill Gates and his goons. Unfortunately, Gates' "buying out" procedure is having his goons destroy Homer's office and break all of his possessions, stating he didn't get rich by writing a lot of checks.
During the trial held by the students, there is insufficient evidence to prove Milhouse ate all the food. Because of this, Bart, acting as judge, acquits Milhouse. The other students are not happy with this verdict and attempt to kill Milhouse. Lisa tries to stop the violence, but gets pushed by Nelson. Bart, angered by this, tells everyone to leave Lisa alone. The other students end up chasing Bart, Lisa, and Milhouse into a cave, where it is revealed that Milhouse's "monster" is actually a wild boar. On one of the boar's tusks is an empty bag of chips, revealing that it was the actual culprit in eating the snacks. Nelson apologized to Milhouse for the misunderstanding mistake they made, who reveals that he only took "two sandwiches and a bag of Doritos" and left the rest of the food to the others. They then kill the boar and eat it (with the exception of Lisa, who adheres to her vegetarianism and licks slime from a rock instead). The episode concludes with a comically obvious deus ex machina ending, narrated by James Earl Jones:
So the children learned how to function as a society,
and eventually they were rescued by, oh, let's say...Moe.
This is a plot loosely based on the book Lord of the Flies, by William Golding. Most of the episode's plot, namely a group of children trapped on an island, is a reference to William Golding's 1954 novel Lord of the Flies. The title comes from the 1981 film Das Boot, although it would be "Der Bus" in German. When the children are squabbling in the classroom, Principal Skinner restores order by banging his shoe on the desk, parodying the shoe-banging incident by Soviet leader Nikita Khrushchev at the UN in 1960. When escaping from the other children, Bart, Lisa and Milhouse have to swing across a gap on a vine; Milhouse goes across first, but refuses to throw the vine back in a reference to the opening scene of Raiders of the Lost Ark (1981), where the same thing happens to Indiana Jones. Ralph's painted face is similar to that of Kiss member Peter Criss.