Ms. Frizzle’s class is currently shrunk down inside of Wanda’s bathroom, though when they hear Wanda’s mother coming, they must try to escape before they are seen. Grabbing whatever materials they can, Ms. Frizzles coordinates the groups efforts as they learn how to build a solid structure so that they can climb it to escape, though things take a turn for the worse then they discover that Wanda’s mother keeps an alligator in the bathtub.