Douglas Milton is writing a book revealing matters relating to security and terrorism, that many authorities and organisations would rather be kept secret, which makes him a prime assassin's target. Jeff and Jeannie get an assignment to protect him from harm until he makes the revelations public at a prestigious international conference.

Harry Wallis was once the partner in the police force of Marty's father, Larry Hopkirk, until Maurice Crabbe killed Larry and disabled Wallis, in revenge for their killing of his brother, the hardened criminal Sidney Crabbe, though Maurice is also left severely disabled by the incident. Marty's tuition from Wyvern concludes, and he is then able to enter Limbo, but there he realises that its attractions are only superficial. Now that Wallis is approaching the end of his life, to salve his remorse he hires Jeff and Jeannie to locate Maurice Crabbe so that he can give him some of his savings to pay for his care.

Jeff's ex-fiancee Freya Cargill asks him to re-open investigations into the death of her Egyptologist father. Jeff and Jeannie head for the museum where he worked, and meet some of the strange staff who work there.

At the request of Bulstrode and Lacey, Jeff and Jeannie pose as doctors to investigate activities at a secret underground pain-research laboratory.