THIS REVIEW CONTAINS SPOILERS FOR SHERLOCK SERIES 4 EPISODE 2. PLEASE PROCEED WITH CAUTION

Since the beginning, with its three-episode series, the second episode in any particular run of Sherlock has largely been considered the worst. Series 1’s “The Blind Banker,” while perfectly competent, failed to capture the greatness of “A Study in Pink” or “The Great Game.” In series 2, while I personally really liked “The Hounds of Baskerville,” it was a digression. This changed a bit in series 3’s “The Sign of Three,” which for my money was the best in a strange an uneven season. It’s a bit of a shock, then, that “The Lying Detective” was not only better than “The Six Thatchers,” but might be one of the best the show’s ever done.

Now, if you read my review of “The Six Thatchers,” you know that I didn’t have as big a problem with it as a lot of people seem to have; however, my hope is that nobody could have a problem with “The Lying Detective” which, as I thought the previous episode did so nicely, blends a gorgeous mystery which heartfelt emotion and more twists than you could probably expect to find. This time, though, we get a masterful and truly terrifying villain in a powerhouse performance by Toby Jones. More on him later.

Writer and co-creator Steven Moffat‘s scripts for Sherlock are usually able to be split into three sections: the first offers some confusing time spent in Sherlock’s brain, the second is when the game is on and we find out most of the meat of the plot leading up to us believing the great detective has been outsmarted, and finally we have the the part in which things we took for granted initially are sprung into Sherlock’s ultimate victory. It’s not only classic Moffat, it’s classic Doyle.

So, we have Sherlock totally out of his mind with grief, taking intravenous cocaine, and operating at a level where he’s six steps behind his own brain, and attempting to crack a case he’s not even sure happened yet. The beloved billionaire philanthropist Culverton Smith (Jones) is evidently a serial killer because he confessed to a group of confidants, to whom he’d given drugs to make them forget. But his daughter remembers a bit and goes to Sherlock for help. She gives him all he needs to catch on that Smith is a serial killer, killing with impunity due to his status and wealth, but he needs Watson to spring his final trap…and Mrs. Hudson…and Molly Hooper.

These beginning scenes–which also include Watson going to a new therapist and neglecting to mention that he’s having conversations with a hallucination of his dead wife Mary–are truly fascinating and wonderful. Sherlock is so far ahead, he’s actually gauged where John would be in two weeks’ time to the minute. Hilarious. This also provides the brilliant Una Stubbs to shine as Mrs. Hudson, a character who has become so much more than she ever was in the source material.

Sherlock, we find out later, has been besought to pick a fight with “a bad guy,” and in this case it’s Culverton Smith. Jones, with fake grotty teeth and a churlish northern accent, is one of the most repellent villains the show’s ever produced, and that’s coming on the heels of Charles Magnusson and Moriarty. The way he relishes “turning humans into things” will put a chill right up your spine, and the joyous way he laughs at the idea of being caught–how could he be? He’s RIIIIICH!–is equally scary. He’s able to make people do anything he wants without ever actually saying anything, threatening his staff by asking how long they’ve worked for him, and turning Sherlock’s every assertion into reason for doubt. Not hard to do with Sherlock being high as a kite. Jones’ performance is just another in a long line of genius turns. If this doesn’t earn him a BAFTA, Emmy, Golden Globe, whatever, then there’s something wrong with the people who vote for such things.

And dammit, yet again the writers of this show manage to make me forget that I’m actually watching a show about a fraternal bond between two co-dependent men and not a mystery story. We’ve never seen Benedict Cumberbatch‘s Sherlock seem more truly guilt-ridden than he is in this story, a “humanity” he alludes to late in the episode. And Martin Freeman‘s ability to play a grief-stricken interior underneath a stalwart, and ever-slightly cracking, exterior never ceases to amaze. These men have wronged each other–much more one-sided, it has to be said–but they need each other, and it’s Mary’s video plea to Sherlock that does it; Sherlock needs to save John by making him save him, and John needs to be the man Mary thought he was. Truly, whatever works.

NOW WE’RE GETTING REAL SPOILERY SO AGAIN, YOU’VE BEEN WARNED

But, of course, a lot of the confusing first act was merely to set up the hugely revelatory ending. The greater mystery at hand actually had nothing to do with Culverton Smith, but instead with who the “daughter” was who spent that evening with Sherlock, giving him the clues and making him realize that a life belongs to others, not the person themselves. But, if you were paying attention, you’d recognize that it wasn’t Smith’s daughter at all, and when the real daughter comes in at the end of the second act, it’s slammed back to us.

So who was she? Not only a false Smith daughter, but a false Watson therapist, and a false Watson flirtation. But more importantly, we learn at the very end, she’s a for-real Holmes sister. That’s right–SISTER, Euros Holmes (played in all cases by Sian Brooke). We were thrown off the scent by the continued word “Sherrinford,” which one would assume is the name of a third Holmes brother, and even John himself appears to believe it’s a brother. A brilliant way to confuse and misdirect. Mycroft deftly avoided pronoun usage ever since saying “the other one” in series 3.

The questions remain: who or what is Sherrinford? Why does Sherlock not seem to know Euros? Will Mycroft actually hook up with Lady Smallwood? And what, if anything, will this have to do with Moriarty? Let us not forget that the third episode is entitled “The Final Problem,” which is the title of the Doyle story wherein Holmes and Moriarty have their thrilling death-inducing tumble down the Reichenbach Falls. But that story was already covered mostly, both in “The Reichenbach Fall” and “The Abominable Bride.” Could calling S4 E3 “The Final Problem” itself be a misdirect? Is the “final problem” really Sherlock’s long-lost, brilliant, and evidently homicidal younger sister?

And, for reals, though–what is Sherrinford, goddammit?!

Rating: 4.5 non-lying burritos.

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Images: BBC/PBS

Kyle Anderson is the Associate Editor for Nerdist. You can find his film and TV reviews here. Follow him on Twitter!