Episode Title:The Magic School Bus Goes Upstream.Episode Description:Ralphie is wondering what happened to all the salmon. They need them for the school fish fry, but they aren't here. The Friz has decided to take the class on a field trip to find out. She turns the bus into a salmon and puts a compact disk in the bus that makes it think like a real salmon, so it will go wherever Ralphie's salmon went. However, when the bus starts migrating, Ralphie changes his mind about doing anything to find out what happened to the salmon. He and some kids in the class attempt to stop it, but to no avail.