THIN ICE begins with a thrilling chase through the Georgetown district of Washington, D.C. An unknown pursuer follows research biologist Mary Clare Ryan around the town; following this scene, her death notice is presented.
The narrative then switches to Nicole, Mary Clare’s sister. She remembers Mary Clare’s return to religion. Nicole had become a student of mythology, perhaps in place of religion. As the story develops, Nicole remembers things about her past and her incestuous relationship with her father that shed light on the career and lifestyle choices she and her sister made.
As Nicole discovers more of the details of her sister’s death, she becomes convinced that it was not an accident, as reported. She finds that she must trust someone if her investigation is to succeed, but at each step she finds herself doubting the intentions of those whom she needs to trust. Her old boyfriend provides useful leads, but he is suspect because it appears as though he had become romantically involved with Mary Clare while still seeing Nicole. A new boyfriend, met during the investigation, at first seems reliable but then reveals a conflict of interest that makes his motivations suspect.
Nicole finally finds that she can trust a policeman and an old acquaintance, a college professor. With their help, she discovers the reasons for Mary Clare’s death and finds her killer. Throughout the book, the reader is alerted to the presence of a tall stranger who is watching Nicole’s progress. This device adds to the tension, making it clear that someone knows what Nicole is up to and will try to prevent her from getting too close to the truth. As well as being a tense thriller, this book is also about self-discovery. The subplot of Nicole’s realizations about how her father’s incestuous behavior has affected her life is convincing and adds depth to her character.