BBC Pictures

This story contains spoilers through the most recent episode of Sherlock.

Christopher Nolan is a truly brilliant British creative talent, which makes it all the more ironic that his work seems to have (at least temporarily) unmoored two of that nation’s greatest fictional heroes. In dampening the palette and tone of superhero movies so spectacularly with his trilogy of Batman movies, Nolan created a domino effect that stretched all the way across the ocean, transforming James Bond from a louche, debonair intelligence agent into a tortured, self-medicating hitman, compelled by the death of his parents to hunt down a series of increasingly psychopathic villains. And, as “The Final Problem” revealed on Sunday, Nolan’s influence has similarly transformed Sherlock. A wry detective drama with a twist has turned into a superhero origin story, complete with agonizing childhood trauma, terrifying antagonists with improbable powers, and a final showdown in an ancestral home burned to the ground.

Mark Gatiss, who co-created Sherlock with Steven Moffat, and who co-wrote “The Final Problem,” in addition to playing Sherlock’s brother, Mycroft, has hinted before that Sherlock exists in the same fictional universe as James Bond. At the end of season three, Mycroft defends his brother by saying, “As my colleague is fond of remarking, this country sometimes needs a blunt instrument.” The comment alludes to “M,” the head of MI6, who once derided James Bond using the same language, but it also seems to explain what made the fourth season of Sherlock such a mess. Sherlock Holmes is anything but a blunt instrument: He’s the embodiment of brains defeating brawn; of observation and intellect, not firepower, saving the realm. The last three episodes of Sherlock, by contrast, have obsessed over their hero’s emotional and intellectual vulnerabilities, and in doing so have lost touch with what made the show so dazzling to begin with.

It’s a problem that seems to have begun with Mary (Amanda Abbington), introduced as John Watson’s fiancée in season three in “The Empty Hearse,” but then unmasked as a former superspy and freelance assassin in “His Last Vow.” That revelation tipped Sherlock from heightened realism into implausible, comic-book inspired fantasy, complete with a grotesque villain holed up in an architecturally splendid hideaway. The most ingenious scenes in that season showed Sherlock (Benedict Cumberbatch) retreating into his mind palace to reason his way through a series of head-scratchers. But, in the end, brawn triumphed. Sherlock, unable to defeat a tyrannical media baron through brainpower alone, shot him in the head, declaring himself to be a “high-functioning sociopath” in order to justify the act.

The moment seemed to crystallize Sherlock’s evolution (Mycroft’s “blunt instrument” comments came in a scene not long after). And season four’s three episodes have doubled down, focusing largely on the tribulations of the show’s main characters and nodding only occasionally at intriguing puzzles. It’s no coincidence that “The Lying Detective” was the best work of the season—it was the only episode that actually presented Sherlock with a substantial case, namely a monstrous millionaire moonlighting as a serial killer. By contrast, “The Six Thatchers” dealt almost entirely with Mary’s past before dispatching her to provide narrative trauma for Sherlock and John (Martin Freeman), while “The Final Problem” was a climactic mess, seemingly indulging the writers’ instincts to have a lark, consistency be damned. “You got a lot of actual plot for your entrance fee,” Moffat told Entertainment Weekly. “The final sequence running around trying to stop a plane crash, trying to solve a puzzle, and John Watson drowning — I just thought it was breakneck and fun.”

I wrote two weeks ago about being disappointed with Mary’s death, and wondering why such a brilliant show has such problems fitting intriguing female characters into its universe. The emergence of Eurus (Sian Brooke) as Sherlock’s secret sister in “The Lying Detective” seemed to signal how wrong this was, but the Eurus of “The Final Problem” was somehow a completely different character still: a bizarre mashup of the supernatural monster Samara in The Ring and Javier Bardem’s Raoul Silva, a wronged former ally intent on revenge, in Skyfall. Eurus, who played three distinct characters convincingly in a previous episode, was suddenly a horror cliché with lank black hair and dead eyes, using mind control to compel others to do awful things, and plotting extravagant riddles for her brother that put his friends in mortal danger.

Things got weaker still when the action suddenly shifted to Sherlock, Mycroft, and Eurus’s childhood home, a pile of stones as stately as Skyfall or Wayne Manor (both of those, you’ll remember, also ended up being obliterated by baddies bearing grudges). John, trapped in a well, discovered the bones of a child (another echo of The Ring), which led Sherlock to discover another memory he’d suppressed, along with any awareness of his sister. Decades ago Eurus, jealous of Sherlock’s closeness with his best friend, Victor, trapped Victor in a well and gave Sherlock a puzzle that would lead to him. But Sherlock couldn’t solve the riddle, Victor died, and Sherlock’s tormented psyche reimagined Victor as “Redbeard,” a dog, while also prompting him to shut down the human side of his personality and clinically investigate crimes for the rest of his life as penance.

It was an episode that resisted attempts to make sense of it. Why did Eurus disguise herself and offer Sherlock clues to a case he was investigating, not to mention disguise herself and try to seduce John Watson? If she managed to escape Sherrinford, the maximum-security island fort where she’d been imprisoned for most of her life, why go back to her cell? Why would she compel Moriarty five years ago to record thousands of convenient gifs and soundbites for a larger plan to get revenge on her brothers but then do nothing when Moriarty forced Sherlock to commit suicide in “The Reichenbach Fall”? Rather than illuminate the complex fabric of the show, as good series finales do, “The Final Problem” poked holes in it, pulling any threads of narrative consistency apart.

It also seemed to conclusively bring Sherlock to an end, complete with a voiceover from the now-deceased Mary essentially declaring that everyone lived happily ever after. Given that it took three years just to get a fourth season, thanks to the stratospheric rise of the show’s stars and their increasingly clogged schedules, it’s fair to assume that new episodes will be a long time coming, if they ever materialize. And, with the direction the show’s taken, it’s easier to say goodbye to it than it might have been a month ago. Modern culture is saturated with superheroes and their nemeses and their gadgets and their secret pain. But Sherlock, at its best, was unlike anything else on air: a celebration of a hero whose primary motivation was simply thinking things through.

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