In the meantime, Morse makes a trip back home to Lincolnshire to visit his dying father. The case is complicated by the appearance in Oxford of an East London gangster named Vic Kasper, an enemy from DI Thursday's past, which reignites a personal feud as Thursday thinks Kasper is somehow involved with the case. The victim had been at odds with his peers over the sale of a piece of college-owned land to a development company in conjunction with the town council. Morse, still on general duties and studying for his forthcoming sergeant's exam, investigates an apparent hit-and-run accident that has claimed the life of an Oxford don. But when an unpopular worker is found murdered in a secluded area of the shop floor, Endeavour must pursue the truth - and then justice - from the sidelines…and in the intoxicating presence of Alice Vexin, an old acquaintance from his days at Oxford.Äecember 1965. The prospect of a visit to Oxford by Her Royal Highness Princess Margaret, who is to unveil the British Imperial Electric Company's new "Standfast" Mark Two missile, has Chief Superintendent Bright, slated to provide security, on red alert. Only a detective of Endeavour's intellect can break them.
As the body count increases, letters containing cryptic clues, goading the police for their failures, are sent to the Oxford Mail. While Oxford city police scramble to find the next potential victim, it seems that Endeavour has finally met his intellectual match. But Detective Constable Endeavour Morse uncovers an underlying method to the madness the elaborate staging of the crimes suggests that the killer shares Endeavour's passion for opera.
An unknown menace stalks Oxford, appearing at first to be just another deranged lunatic, killing at random. Following the shooting of a vicar, Morse is reduced to general duties for dismissing a beautiful, but mentally unstable girl as a suspect and must continue his investigations alone despite warnings of possible dismissal from his superiors. Chief Superintendent Bright, the new commanding officer of the Oxford City Police, unimpressed with Morse's zeal, protests to Thursday that the bagman's position is a Detective Sergeant's job and the young constable is too inexperienced. The sudden death of a secretarial student (Margaret Bell) and the shooting of a doctor appear unconnected despite Morse's theories. Endeavour's superior, Detective Inspector Fred Thursday, recognising the young constable is a detective he can trust, takes him under his wing and is determined to break the case and, with Morse's help, bring it to a successful conclusion. The murder of a 15-year-old schoolgirl and the apparent suicide of her boyfriend lead an investigation by the Oxford City Police to the discovery of sex parties where under-age girls are procured for politicians, businessmen, Oxford dons, and policemen, which in particular make the sifting of evidence very difficult.