Long on atmosphere but short on action, this first novel by former NYPD detective Amato and Sharkey (author of the true-crime book Above Suspicion, 1993) describes the unlikely friendship between a small-time informer and a street-smart New York cop at a turning point in her personal and professional life. When 30-year-old Detective Gerry Conte is assigned to keep an eye on Eugene Rossi, who has promised to rat on his mob-underboss uncle, she feels contempt for the preening, volatile young con and doubts that his information will prove useful. But as time goes by, she develops sympathy for Eugene, who, she realizes, was tricked into cooperating with the police through his naivete and poor reading skills. Meanwhile, Eugene shows a surprisingly gentle side: he helps insecure Gerry gain confidence in her body by taking her to the gym and, through his trust in her, gives her faith in her own judgment--even as their friendship upsets Gerry's live-in lover, a fellow cop who already resents her early success and her ambition to become a lawyer. Whether Amato and Sharkey are describing a seedy Italian pastry shop or the resignation of a hardworking woman who's learned to make the best of an imperfect life, they are adept at evoking places and mood, and the story of Gerry's friendship with Eugene is surprisingly moving. Unfortunately, the plot is episodic and meandering--which makes for a fine portrayal of an honorable cop's workaday life but also for a less than thrilling story. Agent, David Vigliano; author tour; film rights to Sherry Lansing. (July) FYI: Like her heroine, Amato quit her job as an NYPD detective to become a defense attorney.