Second-grader Stink's parents tell him he must play a sport after he gets an unsatisfactory grade in physical education, and so he masters thumb wrestling, as seen on a sports channel.
Judy's big plans for the summer seem ruined when two of her best friends go away, and then her parents leave her and Stink with Aunt Opal, but a new "thrill-a-delic" plan has her racing toward fun.
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.