A package containing disturbing pornographic material is sent anonymously to Chief Commander John Coffin's wife, Stella. So he enlists the help of a trusted colleague and the search for the stalker is on. Meanwhile Coffin is investigating a spate of brutal murders across London - is there a serial killer on the loose? Similarities between the two cases soon emerge and a chilling discovery is made in the grounds of the theatre where Stella is working. Suddenly it seems as though all Coffin holds dear is under threat...