When Judy Moody gets serious about protecting the environment, her little brother Stink thinks she is overdoing it, but she manages to inspire her third grade class to undertake an award-winning, environment-saving project.

Judy is excited about becoming a doctor, especially when Class 3T starts a new unit on the human body, but she learns more about being a patient when she catches tonsillitis from her little brother, Stink.

When a puppy who is being trained as a police dog goes missing, third-grader Judy forms a detective agency to solve the mystery, imitating her literary heroine, Nancy Drew.