As bodies continue to fall and the past bleeds into the present, Dr Alan Twist must confront a killer no one can see and a crime that defies logic. Three young ladies are thrown into raging waters, seemingly pushed by an invisible hand. Six years later, when a famous actor is flung from his window, eye witnesses agree: it was as if he was shoved from behind by an unseen murderer, imitating the inexplicable death of a young lady in the same house over fifty years earlier. Renowned sleuth Dr Alan Twist and his partner Inspector Hurst go to the eerie landscape of Dartmoor to investigate. But invisible killers are hard to bring to justice...