A freak accident leaves the South Park Elementary school bus teetering precariously on the edge of a cliff. As the boys relive landmark moments in their young lives, their bus driver, Mrs. Crabtree, goes for help. A strange turn of events leads her to find the love of her life and her dream job as a stand-up comic.
When the school bus becomes trapped on the edge of a cliff, Ms. Crabtree must leave them alone in order to get help. She meets a truck driver who takes her to the nearest town where she unwittingly ends up as a stand-up comedy act.
Meanwhile, back on the bus, all is not well. A Big Black Scary Monster is slowly harvesting the kids (i.e. Kenny and a kid dressed in a Star Trek redshirt known as the Boy with Red Shirt) while the boys have flashbacks on previous events in their lives, however they are all slightly different to what actually happened and have a recurring theme of ice cream. Ms. Crabtree has now found love with the truck driver and has completely forgotten about the kids.
Eventually, the bus goes over and ends up in a giant ice cream. Cartman suddenly wakes up and realizes it was all a dream. His mom comes to his aid and she reassures him. They then eat a meal of beetles. Stan suddenly wakes up and realizes everything so far was in fact his dream. He rings Kyle up and explains what happened. Back in the fantasy, Ms. Crabtree says to her new found love she wishes she could stay in the dream forever.