Against Marge's wishes, the family stays up for a movie adaptation of "Noah's Ark," which turns out to be a very long (and bombastic) Troy McClure adaptation. The movie runs all night, and a very tired Bart and Lisa head off to school while Homer calls in sick, claiming that his family came down with smallpox. At school, Bart and Lisa are participating in a Model United Nations Club meeting (which doesn't go very well) before leaving for an excursion. During the trip, the children's antics cause an accident; Otto was trying to brake to avoid a steep hill, and when he finally is able to slam on the brakes, the juice from a grapefruit (which had been lodged beneath the brake pedal) squirts into Otto's eyes, blinding him and causing him to steer the bus off a high suspension bridge. The bridge plunges into a river. Otto swims away "for help," but is swept away by a tidal wave; he is later rescued by Chinese fishermen. The schoolchildren, meanwhile, escape the bus and are washed ashore on.