Ruth is one of the only congregants left alive and Morse, by chance, is scouting out the church once more when she enters and is confronted by a mysterious man, with whom she seems to be intimately acquainted, but who attempts to strangle her.
Simon had been left out of a great inheritance from an aunt owing to his wayward lifestyle and had grown vindictive towards Lionel, spreading rumours that the vicar’s behaviour towards choir boys had forced him out of his previous parish.
When she is found dead shortly after arriving, and the Tongue is missing from her hotel room, Morse suspects foul play, despite the doctor’s insistence that she died from natural causes.
Morse and Lewis’s attention is diverted to Theodore Kemp, the colourful museum curator whose naked body is found floating in the River Cherwell the following evening.
The Wolvercote Tongue is retrieved from the river and Morse admits that, despite his prior insistence, there were two cases here rather than one: the original death was simply of natural causes and the subsequent murders were not related to the theft.
When a letter arrives, purportedly from the missing girl, with a London postmark, initial inquiries take Morse and Lewis in the direction of a man named Maguire, a former boyfriend of Valerie.
When the deputy head, Cheryl Baines, is found dead at her home, both Lewis and Strange lash out at Morse, whose prior insistence that murder was involved now seems confirmed.
Graham Daniels, another member of the summer school staff, is found dead and Morse begins to suspect that there is a wider plot and that his presence at the college dinner may have been contrived to provide alibis to the attendees.
Morse and Lewis are called to a pub outside Oxford where a young woman named Sylvia Kane has been found dead in the car park, seemingly run over, but with scratches on her face that suggest an attack.
Morse and Lewis realise that the mysterious other person at the bus stop was not a colleague of Sylvia’s, but Jennifer Coleby’s lodger, Mary Widdowson, who works as a nurse at the hospital.
Lady Hanbury, pressured by Morse, claims that Sir Julius's death was suicide and that she and the gardener, John McKendrick, made it look like murder to present a less shameful story to the watching world.
The attic contains a photographic studio and Lewis notices that the pictures being produced are in the style of Sir Julius' classical paintings but feature the au pair Michelle.
Morse and Lewis are encouraged by Chief Superintendent Rennie to wrap up the case quickly because the cause of death was a heart attack, and because Matthew Copley-Barnes, the Master of Beaufort college, is on the police oversight committee.
He explains that he used to work for an industrial chemical company with financial ties to Beaufort College, and that Dr Dear planned to disclose that incidents connected to a cancer-causing fertiliser had been suppressed.
Morse and Lewis attend a celebratory function for the retiring and recently honoured senior policeman Charlie Hillian OBE, who dies later the same evening after a break-in at his home.
She describes how her father was persecuted for five years, losing jobs and receiving nuisance phone calls, and that on the day he lost his fishing knife, which turned out to be the murder weapon, he saw John Mitchell and his son Terrence by the river.
The body of a local artist and restorer, Harry Field, is found dumped in woodland and despite his wife’s claim that he had left her a message just the other day, he seems to have died almost a week earlier.
Morse and Lewis begin their questioning among Harry’s drink-sodden friends including Tony Doyle, a secondary school art teacher who had apparently been lending Field money.
Studying the TV programme further, Morse realises that Rees, Vasilakis and Tuckerman were all in Greece together at the same time, frequenting Nicos’ restaurant and undoubtedly therefore met Maria too.
The case takes a twist when the baby is snatched from the care of Mr and Mrs Papas and soon after Maria is found dead in the river, seemingly killed in a similar manner to her brother.
Reflecting on the TV programme once more, Morse finally connects the seemingly perfect but childless marriage of Randall and Friday Rees with the missing baby and turns up unannounced at their house.
But in a dramatic finale, Randall, Lewis and the translator all turn up and correct the story, revealing that it was Friday who committed the murders and took the baby, fuelled by her jealousy and desperation of not having a child of her own.
It is only when his doctor, John Marriat, returns from holiday to inform Morse that he would have been incapable of pulling the trigger given his condition that suspicions turn to Fallon’s son-in-law, Peter Rhodes.
Alfred Rydale is Lady Emily’s personal lawyer and initially misleads them into thinking the Balcombes were planning to take their company public, which set the brothers at odds with each other.
Morse’s Oxford connections and Lewis’ diligent police work establish a slightly different story which involves underhand dealings by James that have led to his removal from his role in the company.
Meanwhile, Dr Julian Storrs and Denis Cornford are two candidates locked in an intense rivalry for Master of Lonsdale College, to replace Sir Clixby Bream who is about to retire.
The same night, Morse meets his long-suffering girlfriend Adele Cecil to discuss the previous day's events about the deaths of Rachel James, Geoffrey Owens and Shelly Cornford.
During a lecture by Dr Millicent Van Buren, a visiting professor from Boston University, Morse starts to feel ill, and is later found by Strange collapsed on the lavatory floor.
To pass the time in his recovery, he reads Van Buren's book on Victorian investigation techniques, which details the 1859 murder of Joanna Franks, whose body was found floating in the Oxford Canal.
Consulting Dr Hobson, Morse discovers that Joanna's shoes were not appropriate for walking outdoors and would not have fit a woman of the height indicated by the length of her dress, which had been altered, and the coroner's report.