BLOODSTREAM Author:Tess Gerristsen Gerritsen leaves the urban hospital setting of her first two successful thrillers (Harvest; Life Support) and steps into Stephen King territory the troubled Maine town of Tranquility with mixed results. The former doctor's ability to create credible characters and make medical details accessible and exciting provide the book's strongest moments,... more » as Dr. Claire Elliot recent widow from Baltimore tries to make a go of her new life in Tranquility, where she has moved to get her son Noah, 14, away from dangerous influences. Irony of ironies: the country turns out to hold more savage dangers for the teen than the city ever did. Claire's struggles with the boy, her failure so far to win a place for herself in the hearts of prospective patients and a possible romance with the town's police chief are straightforward and moving. Harder to swallow is the book's premise?that savage outbreaks of violence among Tranquility's teenagers occur every 50-odd years, caused by natural or even supernatural factors. It's Claire who makes the connection between recent murders and older attacks, and of course there's the old "enemy of the people" subplot about not scaring off the tourist trade. The fact that Tranquility's teenage problem has a scientific solution lets Dr. Elliot have a final moment of triumph, but you can't help feeling that King would have made the story more powerful and more fun. Major ad/promo; author tour; Doubleday Book Club and Literary Guild super release; Mystery Guild main selection; simultaneous Simon & Schuster audio.