Cornwall, Today: Arthur Drake finally has time to think about the Invisible Detective and a past life that seems somehow linked to his own. But then he meets the ghosts of sailors shipwrecked over a century ago London, 1937: Whatever your problem, the Invisible Detective can find the answer. Only four children know the truth about this mysterious private investigator because they created him. Now they solve crimes and mysteries in his name. An extraordinary pocket watch that seems to rewind time itself leads the children to investigate a strange clock shop. But what appears to be wrong with the shop's customers, and how are these events linked to a shipwreck in Cornwall? Only the Invisible Detective can find out...