The suspicious death of a hospital patient leads to post mortems being conducted on other patients who supposedly died of natural causes but now appear to have been murdered. Tony suspects the killer may be a person who believes they are releasing the victims from pain by their actions, guided by religious motives. However Islamic terrorists are also suspected, leading to the involvement of MI5. Carol is under scrutiny and needs Tony's help to keep her job.

Tony attends a conference of psychologists, where he is a guest speaker and where he meets an old friend Rachel White, another delegate. He has drinks with her in her room but leaves before having sex. Next morning she is found dead and he was the last person to see her alive, marking him as a suspect. Then another psychologist is also murdered whilst Alex investigates a serial killer whose targets are prostitutes.

Tony is allowed to assist in the investigations. He sees the murders as ritualistic as 'Power Not Truth' was written in the dead doctors' blood. He also begins to see a connection with the murders of the prostitutes and, against Alex's advice, offers himself as bait to trap the killer.