After the body of Dr Stephen Black is found on an Oxford tour bus, DI Lewis and DS Hathaway are lead to Crevecoeur Hall, a sprawling Oxford estate where Hathaway spent much of his childhood. Lewis begins to worry that a previous case involving the murder of a ten-year-old girl has begun to affect Hathaway's state of mind, while Hathaway himself seems more interested in the glamorous Scarlett Mortmaigne, the daughter of the owner of Crevecoeur. When another body is discovered on the estate, Hathaway's refusal to believe that the family are involved threatens to tests his relationship with Lewis to breaking point.

When Andrew Crompton, amateur astronomer and Master of Gresham College, is found dead at the foot of the University Observatory stairs, Lewis and Hathaway find that the finger of suspicion points at all the staff - from tutors right down to the head porter and the college scouts. Lewis uncovers a college-wide blackmail plot and is confused by a mysterious astronomical conundrum. Hobson is unexpectedly drawn into the case while rehearsing for a performance with a local orchestra at the college.

Over an August Bank Holiday, an empty Oxford college is the venue for a weekend attended by professional quiz contestants. Lewis and Hathaway are called in when outstanding competitor Ethan Croft is found floating dead in the college fountain. They learn that Croft was an outrageous flirt with a number of secrets, and the pair race to uncover the killer before the gathering breaks up. Meanwhile, Hathaway discovers that Lewis was planning a romantic weekend at Glyndebourne with a mystery date.

On Halloween night, a university friend of pathologist Laura Hobson is found staked through the heart. During their investigation, Lewis and Hathaway are approached by a medium who claims that they are in grave danger. The following day a student is murdered in the house that Hobson shared with her university friends, and a clue at the crime scene leads Lewis and Hathaway to a third victim. As the body count rises Lewis and Hathaway are forced to acknowledge that Hobson might know more about the deaths than she is letting on.