When Dr. Claire Elliot moves to the rural town of Tranquility, Maine, to open her practice as a family physician, she expects to be able to give her teenage son a new chance in life away from the problems of the city, the wrong crowd of friends, and memories of his father who died. What she encounters instead is her son’s biology teacher being shot to death by a student and a realization that violence repeats itself in a pattern in this town. Claire, as the accused murderer’s doctor, notices medical abnormalities that indicate something is wrong with her patient’s blood, but tests show that the problem is not drug-related. Claire is thwarted in her efforts to delve deeper into the puzzle when the child’s parents suddenly assign his care to another doctor. In a move that could risk her medical license, Claire draws blood from the boy and sends it to the lab to be analyzed. The lab report rejects the doctor’s theory that the child’s psychosis could be linked to a blood anomaly. Then a second boy starts to exhibit similar violent behavior, and the doctor begins to wonder whether nearby Locust Lake could be harboring a deadly organism that invades the bloodstream of the youth who swim in its polluted waters. Her own son swam in that lake last summer, and he is beginning to experience violent mood swings. Will his behavior turn as deadly as the others? Readers should prepare for sheer horror mixed with spine-tingling action in this medical thriller.