A group of young urban explorers and a private military unit could become the final pieces in a 60-year plan to reopen a door that should have stayed closed. But what they unleashed could almost tear our world apart.

During a lecture tour to London, an American psychologist decides to look up her hitherto unknown half-sister and find out about her father who died 10 years earlier. But as she delves into the truth surrounding her father's death she encounters a family that has created a wall of secrecy and lies.

Inspector Robert Lewis and Sergeant James Hathaway solve the tough cases that the learned inhabitants of Oxford throw at them.