Matt and Maggie discover their grandfather's circus trunk containing a magic written incantation, which, when spoken out loud while reaching into the chest, enables them to have hands-on exploration of various careers.
When their old television set finally breaks, Matt and Maggie do not know what to do until Grandmother advises them to invent things that will keep them from being bored.
Matt and Maggie's friend Fergo the gopher wants to be a circus juggler so much that he never stops practicing, and he finally gets a chance to demonstrate what he can do.
After spending the summer eating junk food and staying indoors, Matt the Rat discovers that he is out of shape when school begins again, but with the help of friends and family, Matt learns the value of a healthy diet and exercise.
The Magic Cloud teaches Matt and Maggie about air pollution, the greenhouse effect, and other environmental problems people cause, giving them ideas for how they can make a difference, such as conserving energy at home and planting trees.