Anne Stavely, a fellow chorister and romantic interest of Morse, is found hanged at her home in Jericho. Her death is presumed to be a suicide, but Morse investigates despite not having been assigned to the case. While searching for a suicide note at her home, Morse encounters Sergeant Lewis, beginning their lifelong partnership.

Morse convinces DCS Strange that he is not involved in Stavely’s death and takes on the case. The suicide note was taken by neighbour George Jackson, who uses information from the note to extort money from Stavely’s former employers, Alan and Tony Richards. The choir meets shortly after Stavely’s death and Morse is introduced to Alan Richards, providing Richards with an alibi when Jackson is found to have been murdered at the same time.

Morse is distracted by the presence of the book Oedipus Rex on Stavely’s bedside table and theorises that Ned Murdoch, a local musical prodigy taken under Stavely’s maternal care, caused her death. Lewis is sent to find out whether Murdoch is, in fact, the son that Stavely gave up for adoption, and to take fingerprints of Tony and Adele Richards, but both come to naught; Stavely’s son lives in Wales and the Richards' fingerprints do not match any taken from the Jackson murder.

While reviewing his findings to Morse in front of the Richards brothers, Lewis inadvertently cracks the case by introducing himself to Alan Richards, revealing that the brothers had switched identities to avoid suspicion, and that Alan had killed Jackson to protect his brother and, perhaps, their firm’s reputation.

When Nicholas Quinn, a deaf member of Oxford’s Foreign Examinations Syndicate, is found dead at his home, Morse presumes murder and Quinn’s fellow syndics soon become suspects. Morse and Lewis investigate the movements of the staff on the Friday afternoon in question. The staff consists of Martin, Roope, Ogleby, Bartlett (the secretary) and the attractive divorcee Monica Height. Noakes, the caretaker, swears he saw Quinn leave the offices late on Friday evening, but he actually only saw a man in Quinn’s coat drive away in his car.

Ogleby seems the most suspicious under questioning, but Morse is delighted to discover his alter ego is the crossword setter Daedalus, with whom Morse has matched wits for years. After this initial questioning, Ogleby is brutally murdered.

Morse and Lewis surmise that exam papers have been leaked to the education department of Al-Jamara by Quinn’s predecessor Bland, that Quinn discovered this and told Ogleby, and that this was the cause of at least one of the murders. When Quinn was killed, Ogleby investigated and was also murdered.

Morse confidently, but mistakenly, arrests Roope for Quinn’s murder. Roope's alibi, which is that he arrived in Oxford late on the afternoon of the murder, is confirmed by a college dean he met on the platform, and he is released without charge. Roope meets Dr Bartlett soon after, and Morse arrests both of them, suspecting that Dr Bartlett needed the illicit income to pay for treatment for his mentally unstable son.

Morse realizes that "Donald Martin" and "Doctor Bartlett" would be difficult for a lip reader such as Quinn to distinguish, that Quinn made this mistake, and that Martin committed the murders with Roope as his accomplice. Morse confronts Martin at his home and ends up in a violent struggle, from which Lewis saves him.

Morse and Lewis are called to St Oswald’s where the churchwarden, Harry Josephs, has been seemingly stabbed by a local vagrant following a service. However, it transpires that things might not be as they seem when Max the pathologist informs Morse that the man had enough morphine in his system to kill him before the knife even entered his chest. While the hunt for the vagrant begins, the vicar, Lionel Pawlen, and his congregants are all eyed with suspicion.

Tipped off by another vagrant that the missing prime suspect may be, in fact, the vicar’s brother, Morse invites Pawlen in for questioning, but he summarily throws himself off the church’s steeple instead. Meanwhile, Morse takes a romantic interest in the church caretaker, Ruth, who seems amenable to the attention, but is somewhat evasive.

The bodies soon begin to pile up as Paul Morris, the organist, Brenda Josephs, with whom he had been having an affair, and even Morris’s son are all found dead, and Morse is no closer to solving any of the crimes.

Eventually, with Ruth being one of the only congregants left alive, Morse, by chance, is scouting out the church once more when she enters and is soon confronted by a mysterious man, with whom we know she is intimately acquainted, but who attempts to strangle her, anyway. Morse awkwardly attempts a rescue and a struggle ensues, resulting in a confrontation at the top of the church’s steeple. Morse, we earlier discovered, is afraid of heights.

While this psychopathic killer tries to put an end to Morse, Lewis rushes in to hit him over the head and watch him stumble over the edge to his death.

As they take away the final body, it is only Morse who has realised who this killer is: Harry Josephs, the original "victim" who never was.

It is revealed that Lionel Pawlen and his congregants were all in on the original murder, that of Lionel’s brother, Simon Pawlen, the vagrant. Simon had been left out of a great inheritance from an aunt owing to his alcoholism and wayward lifestyle, and had grown vindictive towards Lionel as a result, spreading rumours about the vicar’s behaviour towards choir boys that had forced him out of his previous parish.

The original murder, then, was an elaborate way of getting rid of Simon, and Lionel used an invented church service, The Feast of the Conversion of St Augustine, and his congregants as co-conspirators, with whom he would share his wealth, to execute the plan.

Since it was Harry Josephs that the congregants agreed falsely to identify, the psychopathic Josephs used this cover to exact revenge on his wife, Brenda, and her lover, Paul Morris, and Morris’s son for good measure. Lionel’s death was indeed suicide, gripped by the guilt of his brother’s murder and suspecting that his deceit would soon be uncovered by Morse.

A tour group of geriatric Americans descend on the Randolph Hotel, including a lady who is about to donate a priceless artefact, the ‘Wolvercote Tongue’, to the Ashmolean Museum. 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.

The chief suspect, Eddie Poindexter, the dead woman’s husband, soon goes missing, and 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.

Morse is convinced he now has two murders on his hands, both connected to the theft, but his guesswork is mere speculation. Kemp’s disabled wife commits suicide after learning of his death, and Morse finally stumbles into a fruitful line of inquiry by considering the movements of the other expert connected to the tour, Cedric Downes, and his wife, whom Morse and Lewis happen to intercept as she makes her way to London with a suitcase.

When they confront Downes on the platform of Oxford station later the same day, and his account of his awareness of Kemp’s death doesn’t match his wife’s, he’s taken in for questioning. That’s not before he literally bumps into Poindexter, who coincidentally steps off a train as Downes attempts to make an escape.

The confessions from Poindexter and Downes are forthcoming. Poindexter admits that his wife’s death, unsurprising given her heart condition, occurred in his presence, and that he took the Tongue in order to throw it away and collect the insurance money. His disappearance was also for the purposes of connecting with his long-lost daughter.

Downes claims that Kemp’s death was an accident and occurred after a confrontation when he had returned home to collect his notes for his lecture, only to find his wife with Kemp in flagrante. With a little bending of the truth from Morse, he also admits to subsequently killing his wife while she was disposing of Kemp’s clothing in London.

As the episode draws to a close, 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 at all.

Based on an original story by Colin Dexter, which he subsequently novelized as The Jewel That Was Ours.

Valerie Craven, the daughter of a local building magnate, has been missing for six months, and so an otherwise idle Morse is assigned the case.

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 one-time boyfriend of Valerie. Reckless guesswork from Morse surprisingly strikes home, and it is established that the girl is, or at least was, pregnant.

Further investigation centres on Valerie’s school, and a head-strong headmaster, Donald Phillipson, and a former teacher now moved on, David Acum, are added to the list of suspects.

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.

Unexpectedly, it is Phillipson’s wife, Sheila, who is identified by a neighbour as being present at the scene on the evening of Baine’s death, and she is brought in for questioning. Insisting that all she encountered at the home was a body, she tells Morse and Lewis that she saw Acum as she left, waiting in a car around the corner.

Acum is, therefore, brought in for questioning, but, after a couple of pints to aid his thinking, Morse seems content to let him go. He does, however, insist on driving Acum back to Reading and, when Acum claims his wife isn’t home, Morse gladly accepts the invitation to wait for her.

Once inside Morse calls out for Valerie, and, sure enough, she emerges from upstairs, Morse having finally realised that he had already met Valerie when he had called at Acum’s house earlier on, but did not initially recognise her, as she was wearing a face pack at the time.

Valerie returns to find her mother in an altercation with Phillipson and his wife. Phillipson claims that he and Grace Craven were having an affair, and were together the night Baines died, and, despite initially confirming this to Morse, Craven now insists he is lying and that their affair ended months ago.

Valerie corroborates this version of events, explaining that she saw Phillipson as she was leaving Baines’ house on the evening in question.

Phillipson finally caves, admits to a struggle and her accidental death, and is taken into police custody as a result.

While Morse pursues another romantic line of inquiry in the form of Dr Jane Robson, he finds himself on hand at an Oxford college when one of its foreign summer students is murdered.

The Japanese man, Yukio Li, excused himself from dinner and is discovered in his room in a ritual pose with injuries to his hands and feet and a dagger in his chest. However, Max insists the cuts were to hide the fact that he’d previously been bound and gagged and that the lack of blood suggested the man had been dead for some time.

After a cassette tape, in a jiffy bag addressed to Yukio and containing traces of cocaine, is found in the back of the coach, Robson confirms to Morse that he had been to the summer school previously and was a drug dealer.

When another member of staff supporting the summer school, Graham Daniels, is found dead, Morse begins to suspect a wider plot and that perhaps his presence at the college dinner was contrived to give alibis to those present.

As Morse’s suspicions grow, particularly towards Kurt Friedman, a German who another student claims is a ‘phoney’, and Sir Wilfred Mulryne, a don of the college, he is told to drop his investigation by Superintendent Dewar, but this only strengthens Morse’s resolve to crack the case.

Through further pestering of Dr Robson, and some theorising of his own, Morse finally establishes the truth. The death, or at least the kidnap and torture, of Yukio Li was planned by Dr Robson and her brother, the man pretending to be Kurt Friedman, as revenge for the torture of their father in Japan during WWII at the hands of Yukio’s father. Mulryne had disclosed this family connection to Dr Robson previously.

The plan went awry as the doppelgänger they used for the Japanese was overpowered by Yukio who, in turn, pretended to be the doppelgänger himself and escaped. The dead man initially found was, therefore, not Yukio Li after all.

Yukio then used the cover of his "death" to exact revenge himself on those complicit in the plot against him, starting with Daniels and then Michael Robson/Kurt Friedman, who is found dead in the showers. On seeing this, Morse immediately realises that Dr Robson is next and rushes to her aid, only to find that someone has rescued her already by bashing Yukio's head in with a croquet mallet after he had attempted to strangle her.

Morse finds Mrs Warbut, of the college bursary office, in the church, who confesses to turning a blind eye to the plot, and who it is implied finally killed Yukio and saved Dr Robson. Warbut grew up in Japan and was scarred and embittered by the knowledge of what happened to Dr Robson’s father and many others during the war.

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.

An envelope, containing what Morse identifies as a coded letter addressed to Sylvia’s superior at work, Jennifer Coleby, is found in Sylvia's purse. Inquiries begin at an Oxford assurance company. Morse quickly presumes the envelope contained wads of cash.

Meanwhile, the man Sylvia was due to meet for a date on the fateful evening begins to spend money in an extravagant fashion. He soon stumbles into trouble and is brought into the station, admitting he did take the money after discovering Sylvia and even her necklace, but, despite this confession, Morse is unconvinced he could have killed her and lets him go.

Instead, Mrs Jarman, an elderly woman who claims to have seen Sylvia get into a red car at a bus stop on the night in question, recognizes Sylvia on a television appeal hosted by Morse, and contacts the police. After her memory is jogged, she even remembers the registration plate, which takes Morse and Lewis to the home of Mrs and Dr Crowther, the latter of whom Morse has already encountered giving a lecture at an Oxford college.

While Sylvia's hitching a lift with Crowther is established, the connection between her and Jennifer Coleby isn’t until Max, who happens to be related to the Crowthers, tells Morse that Sylvia was due to attend physio at the hospital the following day.

Mrs Jarman had reported that another person had been with Sylvia that night, but didn’t get into the car. Instead, Sylvia had departed with the words “see you in the morning”. Morse and Lewis then 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.

By this time, Crowther has had a heart attack whilst disposing of evidence from his car, and so the episode climaxes at the hospital with Widdowson's confessing to Morse what had really gone on: she and Crowther were engaged in an affair, but with his potential appointment to a senior post at the University, Crowther wanted to give her money for a holiday so she would be out of the picture for a while, hence the wads of cash (and the coded message, ‘please take it’) in an envelope that was to get to her via Coleby, only for Sylvia Kane to intercept it.

When Sylvia was coincidentally picked up by Crowther at the bus stop, Mary Widdowson didn’t get in; instead, she followed them to see what would happen between them. When Sylvia gets out of the car, Mary confronts her and knocks her to the ground, only for Crowther inadvertently to run over her as he reverses out of the car park.

Although not murder after all, Widdowson is led away by the police for her hand in Sylvia’s death as Crowther regains consciousness in his hospital bed.

Morse and Lewis are sent to Hanbury House, where an upper-class family has apparently suffered a break-in and the theft of a number of paintings.

Sir Julius Hanbury, however, is nowhere to be seen, which is particularly unusual, since he is vying to be the next Master of an Oxford college and the vote is tied.

Exploring the grounds of Hanbury House, Morse is shown into the family mausoleum, and the battered body of Sir Julius is shockingly discovered.

Soon after, Roger Meadows, the boyfriend of the family’s au pair, Michelle, overturns his sports car driving away from the house. Lewis notices that his brakes had been cut.

Two murders then, or possibly one, as, when Lady Hanbury is put under some pressure by Morse’s enquiries, she claims that Sir Julius’s death was suicide, which she and the gardener, John McKendrick, made to look like murder to present a less shameful story to the watching world. The "theft" was similarly part of their plan, and the paintings are later recovered from their hiding place.

Morse is not satisfied by this wafer-thin confession and keeps snooping, particularly around the attic where there happens to be a photographic studio. Lewis’s keen eye realises that the pictures being produced, in the style of Sir Julius’ classical paintings, in fact, feature Michelle. The prior suggestion that Sir Julius might have been blackmailed is now grounded in evidence.

Lady Handbury’s alibi for the night of Sir Julius’s death soon falls apart under Morse’s questioning when she claims to have witnessed Plácido Domingo featuring in Tosca in Covent Garden, while Morse knows this didn’t happen, as he himself was present for the performance.

Caught in her lies, she finally confesses that she'd been having a long-term affair with McKendrick, and that, on confronting Sir Julius in his studio, and discovering what he had been up to, there had been a struggle, and that she had killed him in self-defence.

She then had McKendrick cut the brakes of Roger Meadows’ car in response to his threats to sell the story of Sir Julius, the au pair and the pornographic pictures to the tabloid press.

As the episode ends, Lady Handbury, McKendrick and Michelle are all driven away in police cars, leaving the six-year-old daughter on the doorstep of the stately home, and a weary Morse, looking on and decrying the tragedy she has inherited.

The torso of a man is found floating in a canal at Thrupp. An old university friend of Morse, and now the Master of the Beaumont College, Sir Alexander Reece, asks Morse to investigate the disappearance of the Deputy Master. Based on Colin Dexter's novel The Riddle of the Third Mile.

An old college roommate of Morse, Anthony Donn, comes to Oxford for an annual cricket match, calls Morse after 20 years and wants to get together and talk. They eat chips on a bench, but Donn never gets round to saying what is on his mind, though he tells a zen story. Morse soon gets distracted by a case in which three people are killed in a hate crime in the fire bombing of a radical bookshop. Donn then turns up dead in his college lodging. At first sight, it looks as if he has electrocuted himself, but, puzzlingly, he had a gun in his luggage. His wife says he hated guns. Lewis postpones his leave to go undercover as a college porter and replaces Donn on the cricket team, the Clarets. One of the team members, Vince Cranston, resents this as he is not a gentleman. At the cricket match between the Clarets and the Hearties, organized by another former college friend of Morse, Roly Marshall, Lewis acquits himself well, while Morse dozes. Meanwhile, Lewis had seen Peter Foster searching Donn's room. Both Anthony Donn's widow, Kate, and Peter Foster's apparent wife, Philippa, appear attracted to Morse.

During the cricket match, Peter Foster is found murdered in the changing rooms, stabbed in the chest with a pair of scissors. Morse confronts Philippa Foster, who admits that she is a customs investigator, and that Peter is not her husband, but her boss. Over the previous two years, they have traced regular exports of cocaine and heroin that correspond with the Clarets' tours to the Low Countries. They had not told Morse, as he might have been involved. She persuades Morse to permit this year's tour to continue. When the tour bus arrives at Dover, it is searched, but nothing is found. Meanwhile, Morse has tailed Kate Donn and seen her passionately kissing Vince Cranston. Morse realises that, contrary to E. M. Forster's advice to "only connect", he has to delink the two killings. He discovers cocaine hidden in the seat of the wheelchair used by Roly Marshall and deduces that Jamie Jasper, Marshall's nephew, killed Foster. Jasper worked in international finance and so had the opportunity to obtain drugs in the Far East. Morse then goes to the radio studio where Kate Donn is hosting her chat show and arrests her for murdering her husband. The motive is that she wanted to leave him for Vince, but he threatened to kill either Vince or himself (hence the gun). Morse suspected this, because Vince had given Kate a book on zen with a florid dedication.

The action takes place during the Test match, with commentary by Brian Johnston, which annoys Morse because it deprives him of his habitual music on BBC Radio 3.

A murder at a multi-storey car park uncovers a crime of passion involving a jealous husband, his wife, and her lover. Based loosely on Colin Dexter's novel The Secret of Annexe 3.

The death of a senior fellow outside Beaufort College during an apparent mugging leads Morse to suspect that the prominent environmentalist was killed because of his beliefs. At the same time, Morse senses that there's more than a prank behind the mysterious packages being sent to Master Matthew Copley-Barnes.

Morse and Lewis investigate whether two murders at a family brewery are linked to a proposed takeover bid. Morse uncovers a 100-year-old connection between a long dead magistrate and the original brewery owner.

The same killer appears to have brutally murdered two women separately in Oxford. Commonalities in the murders lead Morse to the owner of a car dealership as the suspect.

Morse becomes the prime suspect when a friend is murdered at a dress rehearsal of Mozart's The Magic Flute, and he is found holding her with a knife in his hand. It soon becomes apparent that one of his old adversaries, Hugo De Vries, is trying to implicate him.

A highly thought-of and distinguished senior officer, Charlie Hillian, has just retired and is writing a book about his biggest cases. During the night after his OBE investiture, Hillian is killed in a struggle in his rural Oxfordshire home. The notes for one chapter of his forthcoming book are missing – the only case in the book which Hillian and his then DS, Patrick Dawson, never solved. That case involved the murder of an eight-year-old girl, Mary Lapsley, and it appears that someone wants that chapter to remain unpublished. The Lapsley case is very personal for Morse, who has never solved it.

The death of a promising feminist cleric highlights a furious ecclesiastical battle of the sexes that Morse discovers is somehow connected with a weight-loss medication.

Local artist, restorer and bon viveur Harry Field is murdered, but who would want to kill a mediocrity? Lewis considers applying for a promotion to inspector, to the obvious dismay of Morse.

A Greek restaurateur is murdered; his sister, accompanied by her baby, comes to Oxford for the funeral. The sister vanishes, and her baby is then kidnapped. Somehow, both are connected with a reconstructed Hellenic trireme.^{[nb 1]}

Morse and Lewis travel to Australia to re-interview a man who has become a protected witness after he testified against a mobster. Questions about the validity of the case arose in England, and now the informant may be in danger. The bank robbery, in which the protected witness was involved and testified regardin, is the subject of the episode.

When Henry Fallon, an Oxford don, commits suicide, Morse discovers he has a painful link with the man's widow, Susan.

Morse becomes the victim of a hate campaign by the press as he investigates the death of a cruel, boorish industrialist.

Morse and Lewis investigate the apparently accidental death of a wealthy tourist in Italy and uncover an antiquities' smuggling racket.

Lawrence Cryer, convicted of real estate fraud, is found dead in a cell at a minimum security prison, Farnleigh. Morse, Lewis and D.S. Cheetham question various inmates, including Cryer's former partners, Bailey and Thornton, who are also incarcerated at Farnleigh and various victims of the fraud. The Farnleigh governor, Hillary Stevens, is also questioned. An inmate, Charlie Bennett, incarcerated for murdering his wife, is suspected of being the perpetrator.

Teen suicides, one of which is Morse's niece, are being linked to the local rave scene. As part of his preparation for the inspector exam, Lewis is temporarily assigned to another inspector who works strictly by the book.

Matthew Brewster, owner of a private clinic, is found dead in his garage with the car engine running. The pathologist discovers that he was murdered. Morse and Lewis question the dead man's wife and son. They uncover that Michael Steppings threatened the victim; Steppings' daughter was declared brain dead while undergoing simple surgery at the clinic. Steppings is interrogated for the murder and is released when Morse substantiates his alibi. Meanwhile, Lewis discovers that Wendy Hazlitt, a nurse at the clinic, had an affair with Matthew Brewster. He also uncovers a set of anonymous threatening letters, using words clipped from newspapers and magazines, which have been sent to the victim. Forensic examinations reveal that one of the letters has been tampered with, and that an extra death threat has been added, using different glue. Morse's investigation leads to the victim's son, and his belief that the son was blackmailing the victim. Morse accompanies Steppings to visit his comatose daughter in hospital, where she is on life support. Morse begins to like Steppings on learning from observation and staff that Steppings devotedly visits her daily, while Steppings is moved when Morse brings her flowers; however, Lewis discovers that Steppings' accusations of medical incompetence against the Brewsters were correct: Mrs Brewster's developing illness made her take time off to rest or visit hospital, and the Brewsters let the not fully qualified Hazlitt act as anaesthetist. Hazlitt was acting in place of Mrs Brewster, who was in hospital on the day of Steppings' daughter's operation. Hazlitt administered the incorrect anaesthetic dose, leading to the daughter's brain damage; however, Dr Brewster spurned Hazlitt's advances, and so Hazlitt decided on revenge: she contrived contact with Steppings and confessed how his daughter's operation was mishandled, hence the earlier unexplained break-in at the clinic, which was Steppings checking the files to verify the dates of Dr Brewster's absences against ops. Hazlitt and Steppings drew up a plan to murder Dr (Mr) Brewster, which involved blackmailing the son, requiring Steppings to forge threatening letters and the son to reveal them to Morse. Meanwhile, Dr (Mrs) Brewster dies after suffering trauma from being told her son has confessed to the murder and been arrested. After Morse realises and proves the son is lying to cover up for the murderer, the son then murders Steppings before Steppings can flee the country. Steppings writes to Morse, confessing, and saying his ex-wife will look after their daughter, which she does by having the life support switched off.

John Peter Barrie, a convicted rapist and devil worshipper, escapes from a prison infirmary by eluding the authorities with several disguises. Morse and Lewis begin a manhunt in an attempt to track him down. They question his prison therapist, Dr Esther Martin, and Humphrey Appleton, a priest and an expert in the occult, who provides them with information on Barrie's state of mind. Meanwhile, Barrie abducts Holly Trevors, wife of Steven Trevors, an odd-job man working for Oxford college, but releases her. Barrie then demands to meet with Dr Martin on Lammas day, a pagan day of ritual fire. Lewis visits an Occult bookshop, where he finds that one of their regular customers is a colleague of Steven Trevors. Morse begins to suspect that someone is helping Barrie, after witness statements reveal that his disguises involve professional theatrical make-up. Meanwhile, Steven Trevors's fingerprints are discovered, previously unidentified, on the police database from an earlier unsolved crime, which is linked to Barrie. On Lammas Day, a group of devil-worshippers are celebrating a Black Mass, when they are suddenly surrounded by a ring of fire, and Steven Trevors is burned alive. The mystery deepens when Barrie's much earlier connection to his prison therapist is revealed.

Neville Grimshaw, an investigative journalist, is found shot dead. Opera diva Gwladys Probert is shot by a sniper during an academic procession, which is witnessed by Morse and Lewis. Morse and Lewis discover that Grimshaw was investigating Andrew Baydon, a prospective major benefactor of the college. An investigation finds that the two shootings are related. Baydon, a survivor of a Nazi concentration camp, is revealed as a collaborator and guard, and Morse suspects that he ordered the killing of Grimshaw, which leads him to realise that Victor Ignotas, a survivor of the same camp, may have unintentionally shot Probert whilst attempting to kill Baydon.

Stephen Parnell, who confessed to murdering five people, is killed in prison, but, in his dying declaration, he claims that he did not kill the last victim, Karen Anderson. Morse learns that the murders were first investigated by DCI Martin Johnson and Lewis the previous summer, but that Karen Anderson's body has never been found. Morse becomes convinced that Johnson overlooked key evidence, and that Karen Anderson's body has been buried in Wytham Woods, and not in Blenheim Lake, as Parnell had stated in his confession. Morse questions George Daley, a witness who found Anderson's overnight bag a week after she disappeared, and turned it over to the police. The next day, Daley is found shot to death in one of the gardens at Blenheim Palace, and Morse is put in charge, because Strange feels as though Johnson may have cut corners in the investigation. Morse and Lewis then interview Dr Alan Hardinge, the bursar of Lonsdale College; Dave Michaels, the groundskeeper of Wytham Woods; and Margaret and Philip Daley, the wife and son of George Daley. When they question Mrs Daley and her son, they touch upon some photos found on Karen Anderson's camera. Lewis identifies the location in one of the photos as Park Town, which leads them to Alisdair McBryde, a local resident. McBryde identifies Dr James Myton, a South African doctor, who seems to have fled the country mid-way through his rental of a local flat and appears in two of the photos. Morse and Lewis discover that McBryde and Myton had encouraged Karen Anderson to pose for nude photographs for them on the day before she went missing. A search of Myton's flat leads Morse to convince Strange to let him search Wytham Woods. When the search turns up some skeletal remains, Morse is convinced that Karen Anderson has been found.

Dr Felix McClure, a retired university don, is found stabbed to death in his apartment. The phone number of "K" is found in McClure's notes. Morse and Lewis begin investigating McClure's college associates and students. These include Ted Brooks, his former scout, who was sacked by McClure for apparent drug dealing; Matthew Rodway, a student who died in questionable circumstances; and Ashley Davies, another student and friend of Rodway, who trains racehorses at Seven Barrows near Lambourn, and was rusticated by McClure. They discover that Ted Brooks has physically and emotionally abused his wife, Brenda, for years. Brenda's daughter, Kay, who is a high-class escort and is engaged to Ashley, had also been abused by her stepfather, Ted, when she lived at home. Morse interviews Kay about her relationship with Felix and Ted. Morse also questions Julia Stevens, a school teacher and very close friend of Brenda, who is dying of a brain tumour. Morse suspects Ted Brooks killed McClure, because McClure had discovered Ted was selling drugs to the students again. Ted disappears from his house, and his body is found in a nearby river. Brenda Brooks confesses to destroying evidence that incriminates her husband in the death of McClure. Morse and Lewis disagree on whether to search for a possible accomplice, who they suspect must have helped Brenda dispose of the evidence. Morse is convinced that Kay, Julia and Brenda were involved in Ted's disappearance and murder; there's just one hitch – no evidence to prove his theory.

Rachel James, a physiotherapist, is shot through a window of her own home while drawing the blinds one Friday morning. 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. Morse and Lewis begin the investigation by interviewing her neighbours and the clinic where she worked. Morse soon establishes that Julian Storrs gave Rachel a Valentine's card found in her possession, and was having an affair with her at the time of her death. Morse also learns from Storrs that Denis Cornford and Adele Cecil, a neighbour of Rachel, were once lovers. The following morning, Geoffrey Owens, Rachel's neighbour, is found shot dead in his house in similar circumstances. Because there is no Number 13, Morse concludes that Rachel James is mistakenly killed and Geoffrey Owens had been the intended victim. Morse also uncovers that Owens supplemented his reporter's income by blackmailing unknown victims. Among Owens' papers, Morse finds a slip of paper in a file with an article he had written about the retirement of Bream. Morse's trawl through the archives leads him onto a case where housewife Alice Martin and her daughter Debra shot Alice's husband Kenneth, a wealthy businessman, and then burned him on his yacht, because he was going to run off with a younger woman. Morse finds out that Alice and Debra changed their names to Angela and Diane Cullingham, to avoid the stain of their past following them – and that Angela Cullingham has since become Angela Storrs.

Morse and Strange attend an exhibit entitled "Criminal Oxford". 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. While hospitalised, Morse is diagnosed with a bleeding ulcer, which his doctor ascribes to his excessive consumption of alcohol. 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. Rory Oldfield and Alfred Musson, two boatmen on a fly-boat on which Joanna was travelling, were convicted of the murder and hanged. Another, Walter Towns, received a last-minute commutation to transportation for life. However, Morse comes to believe that the men did not kill Joanna, and were victims of a miscarriage of justice. With the assistance of Adele Cecil and Constable Adrian Kershaw, Morse uncovers several inconsistencies in the trial. For instance, Joanna had accused the boatmen of being rude and drunk, but was later seen drinking and smiling with them. A fourth boatman on the fly-boat, a teenager who was not charged, testified for the prosecution. 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. Her drawers, which had been described as torn or ripped, were actually cut with a knife deliberately. Kershaw investigates the insurance payment to Joanna's husband Charles Franks and discovers that she had insured herself, and that payment of £300 was made in full to Charles. Morse figures that Donald "Don" Favant, a passer-by when the body was found, and Charles Franks, are aliases derived from Frank Donavan, Joanna's first husband who was a magician and was believed to have died. Don Favant is an anagram of F. T. Donavan. Although Morse is unable to exhume Joanna's body, he travels to Bertraghboy Bay, on the west coast of Ireland, to open the grave of Frank Donavan. When the coffin is opened, there are no human remains.

Yvonne Harrison is murdered in her bed and found by her husband, Frank, her body having been left in a sexually compromising position. Morse, after no progress, is taken off the case after two months, and it remains unsolved. A year later, an anonymous letter sent to the police suggests Harry Repp, who is to be released from prison, may be the perpetrator. Morse's failing health has Lewis assuming a more active role. Paddy Flynn, the cab driver who drove Frank Harrison to his home on the night of the murder, is found dead in a local rubbish dump. Harry Repp is also found dead, in the boot of a stolen car. A local lothario, John Barron, is killed in a fall from a ladder. It is speculated that the three men had been blackmailing whoever killed Yvonne, and that Barron killed the other two so that he could keep the blackmail money for himself. Yvonne's son, Simon, is questioned in Barron's death, but then a teenage boy admits to having caused Barron to fall off the ladder by crashing into it with his bicycle. The police deduce that the Harrison family conspired after Yvonne's murder to stop the blackmailing. The teenage boy is actually Frank's illegitimate son, Roy, who lied to the police in order to get Simon off the hook for killing Barron. Yvonne's daughter, Sandra Harrison, a doctor who had seen Morse a few days earlier, had killed her mother in a jealous rage over John Barron, who'd seen her arrive last at Yvonne's home. Just after uncovering the truth, Morse collapses from a heart attack and later dies in hospital.^[3] Lewis gets a phone call at the airport, where he has gone to intercept Sandra, who is attempting to flee to Canada. Then, as Lewis takes Sandra into custody, she tries to explain her motivations, but he rebuffs her; she tells him Morse will understand, and he shouts, "Inspector Morse is dead!". Wagner's Parsifal accompanies the final scene.