Everybody expects Douglas John MacDonald to be convicted for the rape and murder of schoolgirl Kylie Donovan. When he walks free there's a public outcry. But someone is not content simply to leave it that way. MacDonald is found murdered - his pinkie removed just like his 15-year-old victim's. The police believe it's an isolated incident, until more murders follow. DI Duncan Waddell and his team have to work fast. They know that, guilty or innocent, no one is safe until they catch the vigilante killer.