Despite the title, the bus is not depicted as directly causing the strange events of the field trip as it would be in later books and the television series.

However, after driving through a tunnel, the bus becomes plastered with images of octopuses and everyone inside finds themselves wearing swimming outfits.

However, the kids begin shrinking once they're outside and, once they're each the size of a raindrop, they rain down into a river, which carries them into the town's water purification system.

Once out of the faucet, they are instantly restored to their regular size and the clothes they were in before the tunnel (except for Ms. Frizzle, wearing a bizarre dress covered with octopus pictures).

In the second season of the Magic School Bus television series, the book was loosely adapted into the episode "Wet All Over," which featured a far greater amount of plot.