Inspector Lynley and Sgt. Havers investigate the death of teenager Sarah Middleton who had gone missing two weeks previously. She was found in a lake and had been dead for three or four days. She had also been sexually assaulted. When a second schoolgirl, Kelly Stevens, also goes missing the police fear they have a predator on their hands. The police focus on Guy Thompson had only recently beaten his wife, Tanya. Havers works on gaining the wife's trust while Lynley learns more about the husband's troubled background. As they continue the investigation, there is growing doubt as to just who is the most dangerous.