As an unexploded World War 2 bomb is discovered, a strange a figure appears on the evening train from London to Nottingham and the carriage is transformed to the 1940s. Though easily dismissed as the foolish stories of overworked imaginations, he keeps appearing and the city is gripped by fear. Is he a ghost? A predator? Local journalist, Arlene Bates demands action from the police and, with an uncomfortable reputation for "peculiar" cases, a reluctant DCI Jenner is assigned to investigate. Then the direst predictions are confirmed when Karen Renshaw is viciously attacked on the train, remaining in a coma while the strange figure cannot be found. As Jenner probes Karen's background, old mysteries are opened up and the web of suspicion widens. Is this a lone attack or the first of many? Events in the past and present come together. Time is running out as a fearful deadline approaches.