One hot muggy day, a new superhero appears in Ms. Frizzle's classroom -- it's Weatherman! Actually, it's only Ralphie pretending he has superpowers and can make a huge thunderstorm that would cool things off fast. The kids think Ralphie has flipped out, but Ms. Frizzle is excited about the idea of making weather. Time for a field trip in the Magic School Bus! The bus becomes a flying weather station and takes the class right into the storm clouds. As if that isn't scary enough, the Friz turns over the controls to superhero Weatherman! Before they know it, Ms. Frizzle's class is on a ride that has more ups and downs than a roller coaster!