Part 1: Petite, 15-year-old Cassie Booth vanishes in the midst of her newspaper delivery route. DS Michael Walker's hopes of finding her alive fade when an anonymous tip leads to grisly clues and eventually to a suspect. Meanwhile, DI Pat North - now working on the vice squad and living with Walker - responds to a complaint from wealthy businessman Stephen Warrington, whose pursuit of her turns increasingly persistent and sinister. After North uncovers links between her stalker and Cassie's kidnapping, two men go to trialeach pointing an accusing finger at the other. (Part 1 of 2)