DI Benny Mitchell is attending another pointless course, leaving Sergeant Jennifer Taylor to investigate a string of mysterious phone calls. The caller is targeting pregnant women and taunting them with rumours about AIDS. Jennifer suspects a young man devastated by MS. He knows he will never be able to have children - is he wreaking some sort of cruel revenge on those who can? But why threaten Mitchell's wife, Ginny? She has four children already. Jennifer becomes convinced that Ginny is at risk from someone much more sinister; and a brutal murder increases her sense of foreboding. Meanwhile, Mitchell, barred from taking any part in the investigation, tries to concentrate on a missing person case. But he loses his patience and events hurtle towards an explosive conclusion.