"It's time for Walker Elementary's annual fish fry--and Ms. Frizzle's class is planning to bring salmon. But there seem to be no salmon left in the sea. Where did they all go? And why? In order to fish for answers, Ms. Frizzle turns the bus into a salmon. And suddenly the gang joins a whole group of real salmon on their way to a freshwater stream--they're migrating! Join the kids and the Friz as they follow salmon on an incredible journey!"--Cover.