Ms. Frizzle’s class was selected to have their garden featured on the cover of a nature magazine, though Phoebe is upset because her plant doesn’t seem to be growing. In order to gain as much knowledge from the problem as possible, Ms. Frizzle takes the children on a fieldtrip where the magic school bus shrinks down to the size of a ladybug, in which they enter Phoebe’s plant in order to see what the problem is.