"Sherlock" star Benedict Cumberbatch in "The Lying Detective"
"Sherlock" star Benedict Cumberbatch in "The Lying Detective" bbc.co.uk

“Sherlock” season 4 episode 1 starts with John Watson (Martin Freeman) trying to cope with wife Mary’s (Amanda Abbington) death. “The Lying Detective” sees Sherlock (Benedict Cumberbatch) squaring off with cunning entrepreneur and philanthropist Culverton Smith (Toby Jones). And yes, the “other Holmes brother” has been acknowledged and given a face at last.

Spoilers ahead for ‘Sherlock’ season 4 episode 1 ‘The Lying Detective’

While Watson is still denying Mary’s death, Sherlock has been on a case to help Culverton’s daughter Faith, who claims her father had a memory-altering drug injected into her. Mary, although dead, still appears on Watson’s head, often giving him advice and imparting wisdom.

Sherlock, meanwhile, appears to be in another drug-fuelled downward spiral, which renders him seemingly ineffective in pinning down Culverton. But just like in Sir Arthur Conan Doyle’s “The Adventure of the Dying Detective,” on which the episode is loosely based, Sherlock has a plan in motion to expose Culverton.

Sherlock has risked his own health to capture a villain and help Watson. This was what Mary had asked him to do in a video message she recorded before she died.

Watson’s progress

Watson started out a broken man, talking to his therapist of his loss but not truly accepting of it. He blamed Sherlock for Mary’s death and was unwilling to help his former best friend until Mrs Hudson (Una Stubbs) used guilt to gain his cooperation.

It took a whole episode for Watson to come around and truly cry over Mary’s death. He even confessed to his non-existent wife how he flirted and wanted to start an affair with a fellow commuter.

The third Holmes sibling is named and revealed

The name “Sherrinford” has first made an appearance in the last episode. And with rumours of a third Holmes brother rife, viewers only had only one conclusion: Sherrinford was Mycroft (Mark Gatiss) and Sherlock’s older brother.

It was even claimed that Tom Hiddleston could play the previously unheard of Holmes brother. And here’s why that seemed unlikely: ‘Sherlock’: The problem with Tom Hiddleston playing a third Holmes brother

There is no need to speculate anymore, though. The mysterious Holmes sibling has been named, but it’s not Sherrinford. “E” from last episode, who was also Watson’s emotional fling/text buddy, has come back. Her name was Eurus, and she’s the Holmes sister nobody talked about.

In “The Six Thatchers,” E’s full name wasn’t mentioned but the credits gave actress Sian Brooke’s character the name of Elizabeth. It turned out the character was hiding an identity that would perhaps make her the deadliest villain in the series yet.

She was revealed to be the same woman who left clues for Sherlock, which means Sherlock’s hallucinations with Culverton’s daughter actually happened, just not with the daughter but with Eurus, and the one who flirted with Watson. She also pointed and fired a gun at Watson at the end of “The Lying Detective.” If she really aimed to fatally wound Watson remains to be seen. The show is unlikely to kill Sherlock’s only friend, but again, the writers can be truly heartless at times.

And now that there’s now a face to go along with the other Holmes sister, it would be great if viewers also get to see Watson’s sister, Harriet. There are names on who could play Harry floating online, but perhaps the most popular is “Doctor Who’s” Alex Kingston.

But who is Sherrinford?

Or perhaps the right question is, “What is Sherrinford?” Mycroft mentioned the name last week and it has appeared again on Mycroft’s notes this episode. But if that name doesn’t mean a Holmes brother, then who or what (place) is Sherrinford?

What’s good and bad in ‘The Lying Detective’

Culverton has been touted as perhaps Sherlock’s most formidable foe since Moriarty (Andrew Scott). He didn’t appear as such, though. Charles Angustus Magnussen (actor Lars Mikkelsen appearing in “The Last Vow”) was even a tougher villain to defeat. Culvernton’s story ended after he was caught. But then again, if there’s one thing “Sherlock” writers do best, it’s to write the unpredictable. So it might not be the last of Culverton’s appearance. Still, Jones’ character was overly hyped,

Sherlock binging on drugs for a case isn’t a new trick as well. It has become predictable of him. There must be a new trick for Sherlock to try.

Nevertheless, the show did a couple of things well. As co-creator Steven Moffat had promised, they would address Watson’s grief properly, and they had. The episode allowed Watson to hang onto Mary’s memory and at the same time let go of her without completely forgetting her. It was a tender and heart-wrenching moment when Watson finally permitted himself to grieve his wife properly and forgive not only Sherlock, but himself as well.

Mrs Hudson has also finally been given more than two sentences of speaking time. She was no longer treated as just a landlady (or a housekeeper, which she never was), she was at last treated as an essential secondary character who could be the voice of reason and the real strength among the heavy intellects. She also owns an Aston Martin and several properties inherited from her late drug lord husband.

“Sherlock” airs Monday on BBC Australia. Season finale “The Final Problem” airs next week.

Read more: ‘Sherlock’ season 4 episode 1 recap/spoilers: ‘The Six Thatchers’ ends in heartbreak with character death, hope with a third Holmes brother

Edited on Jan. 16 to correct the Holmes' sister's name from Eures to Eurus.