The final episode of Sherlock’s fourth and probably final season arrived at last on Sunday night, appropriately titled “The Final Problem.” With it, showrunners Steven Moffat and Mark Gatiss, who also co-wrote the episode, proposed to conclude “the story we’ve been telling from the beginning.”

At its best and at its worst, Sherlock has always bobbled back and forth between feeling like a heavily hallucinatory drug trip and feeling like a modern farce in which problem-solving and a madcap race to solve crimes via the art of deduction have replaced such classic tropes as doors slamming and surprise sets of identical twins. (Fake deaths, however, have remained a constant.)

“The Final Problem,” however, leans so far into both impulses that it collapses into a muddled mess of melodrama and confusion.

Rating 2.5

There’s ultimately not a lot of substance behind all of the sturm und drang that has led to this final episode, and there’s even less logic. There is, however, a lot of high drama and plot shenanigans, and much of it is confusing. Full of frenzied plot twists, “The Final Problem” closed out the season and maybe the series with an episode that — if it really is the last — feels like a huge anticlimax that substitutes implausible drama and showiness for meaningful character development and any kind of narrative payoff.

“The Final Problem” contains a lot of jittery and confusing plot twists

Sherlock’s previous episode, “The Lying Detective,” ended with the surprise reveal that John Watson’s (Martin Freeman) sort-of girlfriend, as well as his new therapist, were the same person. As it turned out, “E” was also the same woman who’d tricked Sherlock (Benedict Cumberbatch) into believing she was a client in the previous episode. All of these women, “shockingly,” turned out to be Sherlock’s never-before-mentioned sister, Eurus (Siân Brooke) — Eurus, as the show took pains to point out, being a Greek word which means “the East wind.” The episode ended on a cliffhanger, with Eurus shooting John at the end of his therapy session.

Rather than picking up right where “The Lying Detective” left off, “The Final Problem” — whose title refers to the famous Arthur Conan Doyle story in which Sherlock kills his nemesis Moriarty — opens instead with a young girl awaking on a strange flight. She soon discovers that everyone else on the plane, including the pilots, have been drugged, and that the plane is now flying on autopilot over unknown terrain, doomed to crash. When she answers a passed-out passenger’s ringing cell phone on the plane, she hears the voice of Moriarty (Andrew Scott).

At some other nebulous point in time, Sherlock’s brother Mycroft (who is played by Gatiss) is watching his favorite film noir when it’s interrupted by mysteriously spliced-in home footage of an early Holmes family picnic and a scary message: “I’m back.” Frightened, he realizes that an assortment of horror clichés have invaded his home: a terrifying ghost girl, an evil clown. (Over the course of the scene, we get one of the most fanservice-y reveals of the series: Mycroft’s ever-present umbrella is really concealing a sword, giving a backpat to years of fan theories that the umbrella was a weapon all along.)

This all plays out like in an eerie dream sequence, but surprise! It’s actually an experiment that Sherlock and John — who, we learn, was shot with a tranquilizer in E’s office, not a real bullet — have elaborately set up using paid actors to frighten Mycroft into revealing the truth: He deliberately hid the identity of a secret sister from Sherlock for Sherlock’s entire life, eventually warning him only that “the East wind is coming” rather than telling him that a psychopathic surprise sibling was gunning for him.

Here’s where we learn how Sherlock failed to recognize his long-lost sister during their drug-fueled all-nighter the previous episode: He’s somehow blocked out any memory of her existence from his mind.

And before we continue, allow me to note that if you’re thinking there must be some logical leaps involved in Sherlock staging a horror film to scare Mycroft into revealing the existence of a secret sibling that Sherlock has forgotten about, you’d better hunker down; this is just the beginning.

John and Sherlock order Mycroft to visit them at 221B and tell them the details. There, we learn that Eurus, a year younger than Sherlock, was an early blooming psychopath who developed what seemed to be a fixation on ending Sherlock’s life or in other ways torturing him. Eurus drowned Sherlock’s dog Redbeard; this is the traumatic incident that caused Sherlock to block Eurus out of his memory. Eurus ultimately graduated from animal cruelty to arson, after which Mycroft insists she was institutionalized.

Mycroft — who was apparently drafted into government service at a very early age and thus able to know his sister’s whereabouts when their parents did not — later told the Holmes parents that she died in a fire at her mental health facility, even though she was really never there. Instead, Eurus was at Sherrinford, the maximum security island prison where she has been held all these years … except for the times when she was able to nip over to London, play elaborate mind games on John and Sherlock, shoot John, and then return to her cell.

This narrative is interrupted by a drone, which Eurus has somehow piloted into the second floor parlor of Baker Street with a motion-activated grenade attached. 221B takes a massive hit, but John, Sherlock, and Mycroft survive, the former two by jumping out the window and Mycroft by hurtling downstairs.

All three of them show up completely unharmed a few quick wacky scenes later (there are pirates involved; it doesn’t make a lot of sense), resurfacing at Sherrinford.

The rest of the episode is devoted to an elaborate series of mind games and “experiments” that Eurus has pulled to get to Sherlock — because in case you’ve forgotten, everything that happens on Sherlock is always about Sherlock Holmes, to the exclusion of other characters having lives or identities outside of wanting to love him, foil him, or mess with his head.

Eurus, it turns out, has also orchestrated the plane takeover during which the young girl wakes up among a sea of sleeping passengers. To have a chance of saving the flight, Sherlock must solve a series of mind games Eurus has painstakingly set up for him (which she accomplished, I’ll remind you, from her unlikely HQ of a palatial prison rock in the middle of the ocean). She’s able to do all of this because merely talking to her is apparently enough to brainwash the prison staff into doing her bidding.

Eurus’s challenges include saving the prison governor’s kidnapped wife, kidnapping three brothers who are all suspected of the same murder (the Garridebs, a reference to another of the original Holmes stories), and rigging an empty coffin to terrorize Sherlock into tricking lovelorn Molly Hooper via phone call into telling him she loves him — a plot point that’s easily and immediately discarded just as Molly herself has always been. (Sherlock does freak out and beat up the coffin over it, but by the end of the episode it’s clear there’s been no real emotional fallout.) Finally, Eurus tries to engineer a situation in which Sherlock has to choose between shooting either John or Mycroft. He settles for trying to shoot himself, but doesn’t get that far.

Several of these “games” end in a lot of gratuitous death. And for no apparent reason other than showmanship, Eurus has filled the prison with a series of pre-taped reaction clips from Moriarty. Moriarty is still dead, but it seems five years earlier Mycroft agreed to let him come to the prison for a brief chat with Eurus, in exchange for Eurus helping him with undisclosed state secrets (why she would be privy to such information isn’t really explained). It’s implied that during their encounter, Eurus let Moriarty in on secrets about the Holmes family that may have allowed him to get closer to Sherlock. Later, she tells him that she is Moriarty’s “revenge” on Sherlock — a subtle way of making her plot all about a man, which is sadly typical of the way Moffat writes female characters.

One of the biggest of these secrets involves Redbeard, Sherlock’s aforementioned childhood dog. Throughout the series, Sherlock’s late pet has been a kind of trigger point for him — it’s been made clear that something mysterious happened to Redbeard, but we’ve never known what. Early in “The Final Problem,” we’re told that Eurus drowned the pup, but in the episode’s final third, Sherlock discovers the truth: He’s not only blocked out the memory of his sister, but the memory of his childhood best friend, Victor. Eurus was jealous of Victor’s friendship with her brother, and drowned Victor at the bottom of a well. This was the real incident that caused her to be institutionalized; to protect himself emotionally, Sherlock created a new version of the incident in which Victor was the lost family dog.

By this point Eurus has mysteriously transported John and Sherlock back to the Holmes family manse and John is chained to the bottom of a well and drowning. To save him, Sherlock realizes one final truth: There is no plane he has to save — it’s been Eurus on the phone all along, mimicking the voice of a scared young girl as a way of communicating her own fragile, tortured mental state to Sherlock.

Sherlock hugs Eurus, which seems to be all that’s needed to get her to throw a rope down to John before he drowns (presumably she also throws him a key to unchain himself, but we don’t see that part). Why this woman who’s killed five other people in a single day suddenly has a change of heart is probably best explained as the result of the miraculous double whammy of Sherlock’s deductive skills and compassion.

Eurus is promptly returned to the same maximum security prison she spent years casually breaking out of. Sherlock visits her. The episode ends with yet another reassuring ‘you two were meant to be together’ monologue from John’s dead wife Mary, in which she calls John and Sherlock her “Baker Street boys” and tells them to go on solving crimes together — which they do in a ridiculously cheesy closing montage that sees them happily partnering up to solve crimes, playing with John’s baby, and having grand times with the rest of Sherlock’s ensemble cast (including a suspiciously cool-with-it Molly).

This is Mycroft’s episode — but he ends up looking completely incompetent

Andrew Scott’s Moriarty has gleefully stolen every Sherlock scene he’s ever appeared in, but “The Final Problem” really belongs to Mycroft. Not only do we learn that he’s got a romantic soft spot for vintage melodrama, has a ninja sword hidden in an umbrella, and once played Lady Bracknell in a performance of The Importance of Being Earnest, but he also gets a couple of stellar comedic moments in this episode. At one point he briefly disguises himself as the world’s most grizzled, chizzled, hilariously accented pirate, and it’s wonderful. The scene in which he tries to convince Sherlock to kill him instead of killing John — by pretending to want Sherlock to kill John instead — is easily one of the most rewarding moments in the entire series.

So it’s more than a bit ironic that “The Final Problem” makes Mycroft seem completely incompetent. His attempts to monitor Eurus from afar have been abject failures, considering he seemingly had no idea she’d been brainwashing the entire staff of her prison, up to and including its administrators. He also allowed her to bargain her way into a meeting with Moriarty because he wanted to use her brain. And he somehow was content with using “the East Wind” as a lifelong spook story to scare Sherlock, instead of ever telling him what Eurus really was. All of this makes Mycroft’s claim to being the clever Holmes brother seem like hubris. The cherry on top is that, at the end of the episode, Mycroft allows Eurus to return to the same prison she repeatedly broke out of. Really?

Mycroft, as the only other Holmes family member who knows the truth about what Eurus did, serves as the liaison between Sherlock’s past and present, between his subconscious and conscious knowledge. And as he explains in “The Final Problem,” he’s been using “potential trigger words to update myself as to [Sherlock’s] mental condition,” without ever really addressing the underlying cause of Sherlock’s emotional rigidity and drug addiction. I’ve written much about what seems to be Sherlock’s perennial failure to make Sherlock actually deal with the consequences of his actions, but this episode really seems to want to force Mycroft to reckon with his own.

On the whole, this emphasis feels lopsided and wrong. Instead of Sherlock having to reckon with the hubris he showed leading up to Mary’s death, or any scrutiny of the dysfunctional dynamic between John and Sherlock that has existed through seasons three and four, we get Mycroft’s parents yelling at him for lying about his sister being dead. Instead of Sherlock having to apologize to Molly for basically treating her like a disposable prop for years, we get Mycroft being frightened into admissions of guilt, not once, but twice. And in the end, there’s not too much suggestion that any of it has really spurred him to change.

All of this is about family, and Sherlock being a real boy

Throughout Sherlock, our hero’s family history has been an ever-present shadow. We’ve always known that there’s a serious amount of dysfunction and distance between the Holmes brothers and their parents, without knowing very well why. Mycroft has reminded Sherlock constantly that he’s always letting his emotions get in the way, but in “The Final Problem” we realize that Sherlock has bottled up considerable emotional trauma — his sister murdering his best friend — for decades.

“The man you are today is your memory of Eurus,” Mycroft tells Sherlock. Eurus is what caused Sherlock to become obsessed with crime-solving, unable to access his emotional core despite having a deeply emotional psyche. Sherlock has famously described himself as a “high-functioning sociopath,” but in reality, he’d just walled off all the background information that allowed his emotions to make sense. At the end of the episode, John tells Sherlock that he “gave her what she was looking for — context,” but really it’s Eurus who contextualizes everything that Sherlock Holmes is.

And who Sherlock turns out to be is a guy who considers John “family,” whose ultimate solution when asked to kill either his best friend or his brother is to threaten instead to kill himself, and whose final reaction when confronted with the woman who put them all at risk is to hug her and then visit her in prison so that they can play violin duets together.

As “The Final Problem” concludes, Lestrade (Rupert Graves) makes a brief appearance to remark that Sherlock is better than being merely a great man — “he’s a good one.” We knew all of this already, but having him reframed as someone whose entire life has been formed by a primal reaction to love and loss makes it even more extraordinary; it makes his heart seem considerably bigger, his compassion realer, and his flaws more understandable than before.

In the past, Sherlock was easy to criticize as the high-functioning sociopath who saw nothing wrong in drugging his best friends and putting himself through the hell of addiction in order to be right about everything, a man whose conscience was an ever-present but often-ignored inconvenience. After “The Final Problem,” all of those actions finally make sense: they were never Sherlock’s attempts to blot out his emotional core; they were his attempts to deal with his struggle and inability to access it.

Unfortunately, while this key revelation may be satisfying on its own, it does nothing to improve “The Final Problem” overall.

“The Final Problem” is an anticlimactic ending to a weird, weird show

Sherlock has always been about showcasing Moffat and Gattis’s love for bizarre plots and zany shenanigans. It’s practically a given that it would end on a logic-stretching plot while simultaneously rolling around in self-congratulatory glee at its own cleverness. But throughout season four, there’s been almost no buildup to anything that happened in “The Final Problem,” and many of the larger lingering questions about the show are nowhere to be found.

The status of the characters’ emotional development, the still-on-hold ramifications of Sherlock murdering Charles Magnussen at the end of season three, John’s new status as a widowed father, lingering questions about Moriarty’s spectral presence, and Molly’s unrequited love — they’re all basically rendered irrelevant by a final montage that seems to reset everything to the jaunty before time of Sherlock’s earlier seasons, as though Sherlock’s faked death, his committing murder, Mary’s death, and John’s subsequent rage and emotional backlash at Sherlock had never happened.

John, in particular, seems to be completely recovered from the internal struggle and angst he’s shown ever since Sherlock’s return from the dead at the start of season three; the last two seasons of conflict and resentment he’s displayed as he’s tried to leave Sherlock’s orbit of dysfunction and establish his own life are nowhere to be found. But if he made his peace with his eternal role as Sherlock’s life partner-in-crime, it happened offstage. And, given how abysmally Sherlock has treated him the entire series, it happened inexplicably.

(There’s also the issue of queerbaiting; Sherlock has done a tremendous amount of it, continually turning the issue of John and Sherlock’s friendship into a running, insulting gay joke. If that was never going to go anywhere, as both Moffat and Gatiss have repeatedly stated it would not, it’s hard to see it as anything but a homophobic running gag at the expense of actual queer identity — even though Gatiss, an openly gay man, has done his part to give us complicated queer characters before.)

Sherlock does its best to sell its heartwarming final moments as a kind of Hallmark card to its fans, a reminder that the game is always afoot and the legend of Sherlock Holmes and John Watson continues ever onward. But following the acid trip of hallucinogenic confusion, fake memories, and melodramatic plot twists that the rest of “The Final Problem” offers, the episode feels like window dressing on a completely different story — the haunted, lonely opium dream of three Holmes children who will never be fully able to tap into different, more authentic versions of themselves.

Watch: How a TV show gets made