 Morse and Lewis investigate the death of Nicholas Quinn, a hard of hearing Oxford examiner who had recently complained to his superior that others in the examination syndicate were selling secrets. Quinn died of cyanide poisoning but Morse is convinced that this is a case of murder, not suicide. When a second prominent member of the syndicate is killed, Morse looks to the other members for the murderer. What he finds is a maze of deceit and office adultery.