When Andrew starts feeling funny after a day at the carnival, Dr. Caruthers tells him and his parents that there may be something wrong with the way his body uses sugar. At first Andrew is scared and has many questions—until the Great Katie Kate magically appears once again to get rid of the Worry Wombat. She introduces Andrew to other kids who also have diabetes, and even takes him inside the human body to explain what's happening to him.
By the time Katie Kate has shown Andrew how to measure his blood sugar, inject insulin, and keep his energy levels up so that he can play with all the other kids, the Worry Wombat has completely disappeared. Armed with the knowledge that he can control his condition, Andrew is no longer worried about having diabetes.
