Outwardly a respectable young family man and Belfast psychotherapist, in reality Paul Spector is the dangerous stalker of lawyer Sarah Kay, breaking into her flat and stealing her undies. The police are called but fail to persuade Sarah to move out. At the same time local officer Jim Burns calls in his English colleague Superintendent Stella Gibson to assist in solving the murder of architect Alice Monroe. Stella sees links between Alice's slaying and that of Fiona Gallagher and suspects a serial killer though not everybody takes her seriously. On the night that the police are called out to discover a cache of weapons in a car Spector, telling his wife that he is going to do voluntary work, kills Sarah Kay with police officers outside her house and unable to get in.