Eleven-year-old Amy has been hiding cookies beneath her bed, drinking gallons of liquid to slake her thirst, getting headaches, feeling irritable, and failing to grow though she's been eating huge meals for months by the time she faints and is taken to the hospital. There she is diagnosed with Type 1 diabetes. Though she feels disoriented and angry, she is immediately put into a training group with other kids around her age who have been recently diagnosed.

She has to learn how to maintain a carefully balanced diet and how to give herself insulin injections. The male nurse who teaches them is himself a diabetic as well as a competent, cheerful young man who takes the edge off the experience. He makes it clear to Amy and the others that the primary responsibility for their health maintenance routines lies with them personally.

After release from the hospital, Amy begins to deal with the social adjustments her disease demands. Her brother and parents are helpful, but uncertain about how much to change their own eating habits to accommodate her. Her younger sister finds the accommodations trying and unfair. Amy's friends also have learning to do.

It helps her that she knows a few other diabetic kids, including Coby, a boy who has struggled with his own resentment and the consequences of sloppy monitoring of his condition, but has learned how to control his diet for the sake of staying on the baseball team where he's a star player. Their friendship helps Amy transition into "normal" life hopefully.