Dr William Adams, an Oxford Egyptologist, and Laura Tennett find their lives under threat after the murder of Laura's boyfriend, Jeremy White, a research student whose doctorate Adams is supervising. While the police seem to be getting nowhere in their investigation, William and Laura escape to a safe house in an attempt to decipher Jeremy's doctoral thesis which may hold a clue to his murder. They are tracked down by a mysterious organization operating within the Roman Catholic Church; their lives are in jeopardy as they discover a secret harbored by the Church for centuries and which threatens to destroy it. Their travels in England and France lead them to the resting place of one of history's most important caches of religious documents, secured by an ancient sect implacably opposed to the Catholic Church. They discover both the riddle and the solution of Jeremy's death ... and so much more.