The principal, Mr. Ruhle, has to go away for a few days and leaves his beloved chicken, Giblets, in Dorothy Ann's care. The Friz takes the class on a field trip to see how eggs are made - from the inside out.
The only contribution the kids in Ms. Frizzle's class have made to the Walkerville Space Capsule is an empty jar. "It's not empty," argues Keesha. "It's filled with air!" Ralphie thinks that air doesn't do anything, but when the bus shrinks and gets stuck inside the jar - the class finds that their only hope for escape is... air!
Should Walkerville get rid of the swamp and replace it with a great new shopping mall or build the mall somewhere else? The class learns that the swamp is an important habitat and natural water filter, but the town council's not convinced until...FLOOD!!
Phoebe is chosen to give a slam-dunk exhibition during the big basketball game. When she finds she can't jump high enough because gravity is "pulling on" her, Ms. Frizzle takes the class into space and turns the Bus into a planet - with adjustable gravity!
Ms. Frizzle's class opens the school for Mr. Ruhle (Paul Winfield). But there's so much to do! "There must be a way to do these chores without actually doing them," says Carlos. Enter Mr. Ruhle's new computer and Mikey, Carlos' whiz kid brother!
Ms. Frizzle's class is visiting the zoo, which is, according to Tim, the only place in the city where wild animals can survive. To test this idea, Ms. Frizzle turns the class into possums, foxes, and falcons.
When Wanda discovers that one of Ms. Frizzle's ancestors was Redbeard the Pirate, she naturally wants to follow the treasure map he left. The map leads the class to a coral reef, where they learn firsthand that life there is risky.