With her parents desperately worried by her moods, withdrawn behavior, and possible drug use, 16-year-old Sophie Hammond is sent as a boarder to a coeducational private school. A talented swimmer, she appears to be settling in well with the help of the young woman who is both her coach and house mother. When Sophie is found dead in her room with both the door and window secured, it is at first assumed that she either took her own life or died from an accidental overdose of the drugs and alcohol which are found in her room. Forensic pathologist Rawlings, however, is convinced that she has been suffocated. Before the answers to the tragedy are found, two further deaths occur, and the lives of all those involved - including the investigating police officers - are turned upside down.