Steven Parnell, who was accused of murdering a number young girls the previous summer, is killed while in prison awaiting trial. Morse had not been involved in the case as he was on leave during most of that investigation. What piques Morse's interest is that one of the victims, Karen Anderson, was never found and it is assumed that her body was dumped in a nearby lake but Parnell confessed to his priest on his deathbed that he wasn't responsible for that particular murder. When one of the witnesses in the case, George Daly, is murdered, Morse and Lewis try to find some connection to Anderson's disappearance. They also wonder why Anderson's camera - she was an avid photographer - wasn't found. What they come across is a group of middle-aged men whose hobby is taking so-called glamour photos.
Morse and Lewis investigate the death of Laura Poindexter, an American tourist who is part of an exclusive tour group visiting Oxford. Missing from her personal effects is her jewelry, including the Wolvercote Tongue which she was going to donate to the Ashmolean Museum. The pathologist determines that she died of natural causes, but Morse feels there's something not quite right. The mystery deepens when Theodore Kemp, the Ashmolean's expert on the Wolvercote Tongue, is found dead and Mrs. Poindexter's husband goes missing.
Felix McClure, an Oxford University professor, is stabbed to death in his college study. Not only was he an expert in his field but he was one of the University's key fund-raisers. The investigation focuses on Brooks, a one-time cleaner for McClure who quit his college job abruptly after a student, Mathew Rodway, jumped out of a college window high on drugs. When Morse learns that Brooks' daughter was the object of affection for both Rodway and another student, he has another possible suspect. Brooks' wife also worked for one of McClure's friends and Morse uncovers a conspiracy that he may not be able to prove.