Following the untimely death of his parents when he is ten years old, Kenneth Mills is forced to live with his grandmother, Esther, in Osprey Cove, Maine. Esther is controlling and bitter, and she and Kenneth repulse each other. What's more, Kenneth is unbalanced; as a teenager, he attacks a fellow student with a scalpel and then spends three years in the Crestwood Insane Asylum, where he is eventually diagnosed as a psychotic schizophrenic.
Following treatment, he returns to the home of his youth. As he grows to adulthood, the townspeople see him differently. They are now scared of Kenneth and fear what he might do to them. He has bizarre obsessions with younger girls and fantasizes about becoming a great surgeon, like Dr. Walters, the town's only physician.
Despite Kenneth's delusions, however, his psychological state may have other causes. The people of Osprey Cove are, in fact, cruel and abnormal-but who's to say what's normal anyway? As he sinks further and further into fantasy, it is impossible for Kenneth to discern reality from dreams. In the end, the question remains: who is the real lunatic of Osprey Cove?