There’s a wonderful moment in one of the old Inspector Morse shows—the one called “Promised Land,” set in Australia instead of the series’ home base of Oxford—when Morse has reached a dead end in his investigation (and in his life as well, more or less), and he’s talking to his sidekick Lewis and calls him Robbie. Which is indeed Lewis’s first name, but in all the many episodes before that, Morse had never called him anything but Lewis—often in a distinctively sneering way: Lyeeewis.

A certain habitual guard has been let down, partly as a result of exhaustion, but mostly, I think, because of location—displacement yields disinhibition. Morse never would have called him Robbie had they remained in Oxford, where the structures of everyday routine reinforced their differences in class and rank. And if he calls him Robbie again later, it is only because of the barrier that came down, however briefly, when they were in the antipodes.

I haven’t seen that episode in 20 years, but I still remember it vividly, in large part because of the reaction of Kevin Whately as Lewis: an almost imperceptible flickering of the eyelids and then the resumption of stoicism. It’s a wonderful bit of acting by Whately, and not only does he not speak, he doesn’t even move.

Whately played Robbie Lewis for the first time when Inspector Morse began, on ITV in England, in 1987, and has now played him for the last time, the sequel-series Lewis having ended in November 2015. There were hiatuses along the way—six years separated the wrapping-up of Morse and the beginning of Lewis—but still, that’s quite a run with a single character, and I’ve been watching pretty much the entire time. The end of Lewis is the end of an era for Kevin Whately, certainly, but also for me.

Neither the original Inspector Morse nor its successor Lewis was uniformly excellent. The productions were clearly done on a strictly limited budget; the plotting was sometimes muddy, often convoluted, and hole-prone. But the acting was always fine, and my wife and I tuned in so regularly not because we were intrigued by any particular mystery but because we wanted to see Morse-plus-Lewis and then, later, Lewis-plus-Hathaway. (James Hathaway, a young policeman assigned to work with the now-senior Lewis, is played superbly by Laurence Fox.) These are buddy shows, but of a high order: Morse acts always on impulse and instinct, like Don Quixote, to whom Lewis acts the grounded and rational Sancho Panza. The Lewis-Hathaway dynamic differs, though Hathaway also has some windmills to tilt at, in a comparatively subdued way.

And then, of course, there is Oxford. When we began watching the show we had never been there, and I would be lying if I said that we did not enjoy the inevitable well-composed shots of the “dreaming spires.” But we were also intrigued by the show’s constant reminders that the famous and ancient colleges are only a relatively small, if disproportionately influential, part of the city’s fabric, and that Oxford as a whole has the social variousness and criminal pathologies that all other cities have. (In one episode Lewis questions a man named St. John. When the man corrects Lewis’s pronunciation—“It’s pronounced ‘Sinjin’”—Lewis, as he departs, and speaking for the rest of Oxford and for his own Northern upbringing, says, “Thanks, Mr. Saint John.”) The contrast between ancient dignity and modern scrubbiness is a good one, visually and dramatically.

Eventually I would spend a good deal of time in Oxford—more time, indeed, than in any city I haven’t formally lived in, more than a year when you add it all up—and I got to know it well enough to appreciate the old Cambridge jab that Oxford is basically “Detroit with colleges.” After that, watching Morse and Lewis became a somewhat different experience: my wife and I still took delight in the development of the characters, but also, now, played Spot the Location. “Ah, that’s one of the side streets off the Banbury Road, before you get to Summertown.” “Oh, I know where that pub is … wait, is that it?” And when we ceased to have so many opportunities to go to Oxford—I’ve been there only once in the past ten years—watching the shows became a way to maintain our connection with a place we’d come very much to love.

These days ITV is keeping the flame alive with Endeavour, the prequel featuring Shaun Evans as the young Morse in his early days as a policeman, in the 1960s. But the show, while quite well done—in some ways, especially in the quality of its production, it’s superior to its predecessors—is manifestly a period piece, offering us Oxford as it was, not the Oxford of today, the city I know. I like the show and I’ll keep watching, but not for all the same reasons that I enjoyed its predecessors.

Still, the makers of Endeavour are generous in registering their debts. In the third episode of the third season, there’s a lovely moment, for old hands, when we meet a young gardener on the estate of the Mortmaigne family. The gardener’s name is Philip Hathaway, and some fans of Lewis will remember that James Hathaway grew up on the Mortmaigne estate, as the son of the estate agent. So a whole story gets sketched in there, quite elegantly, and the generations linked. That’s the sort of connection than an older person, such as I, might be expected to enjoy, and indeed it’s nice to see a television show acknowledge and play to viewers who have been around a while (or who have backfilled the context via Netflix).

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These shows are, it’s often said, old people’s television: Inspector Morse was a favorite of Queen Elizabeth, and I’d be surprised if Her Majesty didn’t keep up with the later developments. The shows do tend to portray middle-aged people falling in (and sometimes out of) love, something that risks alienating viewers young enough to be the actors’ children—that could be Mom or Dad up there on the screen—but I also wonder whether the detective story as a genre is made for people with more than a few years behind them.

Long ago W.H. Auden, in a famous essay about detective fiction, speculated that the fundamental logic of such fiction involves the portrayal of an apparent Eden that is broken by the intrusion of crime, and the specific crime of murder, so that by the intervention of clever and wise persons the social world can be healed and order restored—but not the original order since the dead cannot be brought back to life. “Murder is unique” among crimes, Auden says, “in that it abolishes the party it injures, so that society has to take the place of the victim and on his behalf demand restitution or grant forgiveness.” This is a kind of legal fiction, this substitution of the society itself for one who can no longer seek, or benefit from, justice: in a broken world, things can never be what they were. But partial restoration is better than none, and hope for it is a reasonable aspiration, one claimed by those who have known what the poet James Wright calls “The change of tone, the human hope gone gray.” The satisfactions of the murder mystery are real but somewhat grim, in ways that perhaps best suit the no-longer-young. They are anything but utopian.

In the murder mystery, society does not simply stand in for the victim, it undergoes its own development, for if the story begins in a seemingly orderly and peaceful world, the operative word in that description is “seemingly.” Its initial state is, Auden says, one of “false innocence,” and a murder does not bring evil into society but rather reveals the evil that is already there. The human tendency to take complacent pleasure in a fictional innocence is something that can best be seen in a small and mostly closed society, which is why so many classic detective novels are set in places like English country houses or long-distance railways or isolated villages, and why the Morse episodes, even ones whose murders do not take place in the university, tend to involve one of the colleges in some way. The root of “paradise” is a Persian word that means “walled garden,” and the older colleges in particular, with their walls and gatehouses and immaculate lawns, certainly hope to present themselves to the world as little Edens. As John Donne said in a 1634 sermon, “The university is a paradise, rivers of knowledge are there, arts and sciences flow from thence. Council tables are Horti conclusi, (as it is said in the Canticles) Gardens that are walled in, and they are fontes signati, wells that are sealed up; bottomless depths of unsearchable counsels there.”

And yet, Donne continued, all such learning, if not directed toward the knowledge and love of God, is “but an elaborate and exquisite ignorance.” The paradise is not what its residents would have us believe: those “Gardens that are walled in” offer many excellent hiding places for serpents. In the Morse and Lewis stories, the (fictional) Thames Valley Police, in its uniforms and business suits, may itself seem serpent-like to the begowned collegiate inhabitants, something other, something that doesn’t belong; but its purpose is to expose the serpents the gardens have inadvertently nurtured—a necessary exposure, but one that also destroys the paradisal fiction. Another blow to utopian dreams.

But of course the investigators are no less fallible than those whom they investigate. Recently I watched “Coda,” the last episode of the third season of Endeavour. In it, young Morse helps to thwart a bank robbery that turns violent. Perpetrators are arrested; the main characters avoid death (though not all the minor ones—a hostage and a policeman are shot). All is not quite well, but, as is necessary to the genre, order is restored. But the episode is filled with curious callbacks, some large and some small, to “Promised Land.” I said above that I had not seen that episode in 20 years, but after “Coda” I decided to rewatch it.

In “Promised Land” we learn that, among the people whom Morse helped put in prison after that bank robbery, one was innocent—and died in that prison, years later, in agony, of AIDS. And the innocent man’s brother goes to Australia to take vengeance on a witness whom the British government had resettled there under an assumed name. But the chief drama of the story lies in this: Morse’s dawning awareness of the role he himself played in putting that man away, and (however unwittingly) sentencing him to death. Morse says to Lewis that he was “blinded” by his own desire for vengeance on the killer of his colleague; and therefore it is only just that he confront the other avenger, the wrathful brother, even though that confrontation might cost him his life.

Lewis tries to dissuade Morse, but Morse is insistent. He reminds Lewis that he has no wife, no children, no attachments; he is, humanly speaking, expendable. And, he says, he is old. Lewis asks, in his typically ingenuous way, “How old are you, sir?”—to which Morse replies: “I forget, Robbie.”

In Auden’s essay on detective fiction he muses on the curious fact that many of its fans have no interest in other “genre” stories—romances, Westerns, science fiction, fantasy—and he speculates that the mystery offers something unique: “I suspect that the typical reader of detective stories is, like myself, a person who suffers from a sense of sin.” In “Promised Land” it is the detective himself who so suffers. At one point in the episode Lewis asks him (again, in this atmosphere of lowered inhibition) whether he believes in God, and Morse replies that he’d “like to believe” in “a just God, dispensing justice.” But that’s as far as he can manage to get.

And so we’re left with a world in which justice is hoped for but never fully achieved, in which sin and crime can be exposed and punished but never, never quite, paid for—at least not by us. Hard lessons, but ones we all learn if we live long enough. In light of the tragedies that unfold with such implacable logic in “Promised Land,” the title of “Coda” seems obviously and painfully ironic because it’s not the ending of anything: the events of that episode are rocks dropped in a pool, and only decades later do the ripples reach the shore. As another broken man puts it in another mystery story—Rust Cohle in True Detective—“Nothing is ever over.”

Alan Jacobs is a distinguished professor of the humanities in the Honors Program at Baylor University in Waco, Texas, and the author, most recently, of The Book of Common Prayer: A Biography.